part 3 - wales (in english)

7/31/2019 Part 3 - Wales (in English)

1/70

Drinking water 2005

Part 3

Drinking water quality in Wales

A report by the Chief InspectorDrinking Water Inspectorate


2/70

Drinking water 2005

Part 3


A report by the Chief Inspector

Drinking Water Inspectorate

June 2006


3/70

Published byDrinking Water Inspectorate

55 Whitehall

London

SW1A 2EY

Tel: 020 7082 8024

Website: http://www.dwi.gov.uk

Crown Copyright 2006

ISBN: 1-905852-08-8

ISBN: 978-1-905852-08-6

PB11881i

Copyright in the typographical arrangement and design rests with the Crown.

This publication (excluding the logo) may be reproduced free of charge in any format

or medium provided that it is reproduced accurately and not used in a misleading

context. The material must be acknowledged as Crown copyright with the title and

source of the publication specified.


4/70


Contents

Letter from the Chief Inspector of Drinking Water to Carwyn Jones 1

Minister for Environment, Planning and Countryside,

Welsh Assembly Government

Introduction 9

Drinking water quality in Wales 11

Water sources 12

Drinking water quality testing 12Drinking water quality results 13

Water quality in distribution 26

Consumer perceptions of drinking water quality 30

Issues of local interest 32

Incidents in 2005 33

Technical audit activity in the region 34

Local authority consultation 36

Consultation with health professionals 37

Annex 1: Other sources of information 39

Annex 2: Glossary and description of standards 41

Annex 3: Incidents in Wales in 2005 55

Annex 4: Water regulation and management MSc 59

This report is Part 3 of three parts published annually by the Drinking Water

Inspectorate. Part 3 consists of regional reports for Eastern, Midlands, Northern,

Southern, Thames, Western and Wales regions.

Part 1 Drinking water standards and science outlines how water is regulated, how

to find more information about drinking water and presents a review of research.

Part 2 Drinking water safety reviews the performance of the water industry in 2005.

All reports are available on the Inspectorates website at http://www.dwi.gov.uk and

on CD.


5/70


6/70

Part 3 Drinking water quality in Wales

1

DRI NKI NG WATER I NSPECTORATE

55, Whitehall, London. SW1A 2EY

Direct Line: 020 7082 8048

Enquiries: 020 7082 8024

Facsimile: 020 7082 8028

28th June 2006

To

The Rt Hon Carwyn Jones AM

Minister for Environment, Planning and Countryside

Welsh Assembly Government

I am pleased to present the 7th report about drinking water quality in Walescovering

the year ending 31 December 2005. Building on the success of the new approach to

reporting introduced last year, this year my report is in portfolio format using a range

of technologies thereby enabling broad community access to drinking water quality

information. I have made public access to information a priority for the Inspectorate

because I believe this is vital to consumer confidence. Below I summarise the purpose

and content of each part of my report.

Part 1 Drinking water standards and scienceis a booklet which explains

straightforwardly how drinking water quality in England and Wales is measured andregulated. Also included is advice on how someone can access the science which

underpins the standards and a summary of Defras Drinking Water Quality & Health

Research Programme managed by the Inspectorate. The booklet, which explains what

someone should do if they have a concern about drinking water quality, will be

distributed widely to public libraries, the Consumer Council for Water and local

authorities.

Part 2 Drinking water safetyI expect this part of my report to be of direct interest to

water companies, policy makers, other regulators and opinion formers. In it, I outline

safe drinking water management practice and report on the performance of thewater industry in England and Wales in terms of this framework using a basket of

measures derived from data currently available to the Inspectorate. This information

reflects the differing challenges faced by each of the water companies in terms of

the nature of their water resources and their water treatment and distribution

infrastructure as well as the influence on drinking water quality of domestic (building)

water systems maintained by their customers. It also contains a summary of the

AMP4 drinking water quality improvement programme.


7/70

Drinking water 2005

2

Part 3 Regional drinking water quality reports.One of my 7 reports is dedicated to

describing the drinking water quality results for Wales in 2005. The audiences for

these reports are local community stakeholders, particularly local authorities and

health professionals, but also importantly members of the regional Consumer Council

for Water committee. This report includes a commentary by the Inspectorate on testresults and water company actions in response to any adverse findings, together with

details of learning from water quality incidents and technical audits carried out by

Inspectors. Details are also given of progress in the year with drinking water

improvement programmes, consumer perceptions and outcomes of consultations

with local authorities and with health professionals.

Electronic InformationA CD comes with the folder that contains the above

mentioned booklets. On the CD are Look Up Tables of the results of drinking water

tests by water company. The CD also provides Parts 1, 2, and 3 of the Report in

electronic format.

Website publicationThe booklets and Look Up tables are available on the

Inspectorates website in downloadable format. The website is also where people can

find the entirety of the Inspectorates guidance, research reports and other facts and

figures of public interest such as our prosecution and enforcement record.

Drinking water quality in 2005As explained in some detail in my report last year, drinking water quality is measured

in zones containing no more than 100,000 consumers. By calculating the mean zonal

compliance % we have a broad measure of overall compliance by water companieswith European and national drinking water standards. For Wales in 2005 this

compliance figure was 99.96% compared to 99.92%in 2004. As a whole therefore

the picture for 2005 is one of improvement from the baseline set in 2004 (the first

year of reporting against the new standards). In 2005 29 parameters compliance was

99.99% or above. For a further four parameters it was between 99.95% and

99.99%. The three parameters with the lowest figures were trihalomethanes

(99.68%), iron (99.70%) and lead (99.78%). The problems reflected by these

parameters do not apply everywhere. Details of their occurrence are described in the

regional report for Wales. Discoloured water due to iron is most severe in the

Rhondda Valley north of Bridgend and the Rhymney Valley north of Cardiff. Problemswith trihalomethanes (disinfection byproducts) relate mostly to water treatment

problems in North Wales (Anglesey) and in Llyswen to the north east of Brecon. Lead

is a more complex subject which I review more fully below.


8/70


3

Meeting the current and future lead standards

The pipe connecting a property to the water company main, together with internal

plumbing, is the main source of lead in drinking water. The extent of lead pick up

depends on various factors; temperature, acidity (pH), water hardness, the length ofpipe and the time that water is left to stand in the pipe (stagnation) before it is drawn

off. Properties built or renovated since 1970 are unlikely to have lead pipes and since

1990 water companies have opportunistically replaced many of their service

connections as part of their water distribution maintenance programmes.

In 1996 the World Health Organisation (WHO) tightened its guideline of 50 g/l for

lead in drinking water because lead can accumulate in the body and this can give rise

to adverse neurological health effects in young children. When setting the new

guideline of 10 g/l, WHO recognised that the permanent solution, removal of lead

pipes, would take time and money to achieve. The view of WHO was that other

practical measures (water treatment) should be introduced in the interim. This WHO

advice was adopted formally in Europe through the 1998 Drinking Water Directive,

which set an interim standard of 25 g/l (December 2003) and a final standard of

10 g/l (to become effective in 2013).

In Wales phosphate dosing was adopted as the most cost effective way of treating

the water to make it less likely to dissolve lead from pipes and solder. The companies

have now installed phosphate dosing in most places where the need has been

identified and during 2005 dosing levels have been optimized. The extent of supplies

now being treated is illustrated by a map in each of my regional reports this year. It is

important to realise that the risk of consumer exposure to lead is limited to only thoseproperties with lead pipes. Consumers wishing to have their water tested for lead can

approach their water company who will arrange for a sample to be taken.

All the work done on lead to date has resulted in an overall improving trend for

England and Wales shown in the figure below. Looking towards the future and based

on monitoring during 2005 only a very small fraction (0.26%) of tests now give

results above the tightened interim standard of 25 g/l and the number of tests

failing the future standard of 10 g/l is in decline.


9/70

Drinking water 2005

4

England and Wales: Percentage of tests meeting the current and future standard for

lead 2001 to 2005

Meeting the lead standard everywhere by 2013 will be a complex matter because not

all owners of buildings will choose to invest in replacing lead pipes, even when

notified of an adverse test result by their water company. However because by law

water companies notify local authorities of the location of every sample containing

lead above 25 g/l the Inspectorate is recommending that the way forward is for

local authorities to begin actively reviewing this information. To assist this process amap of the location of samples exceeding the standards has been included in each

regional report. Local health professionals are best placed to determine if any

additional action is justified to reduce exposure to lead in a particular community.

Locations of particular interest might be social housing and public buildings such

as schools.

Public buildings

For several years there has been debate in the industry about where responsibility

should lie for testing drinking water quality in public buildings. This controversy has

its roots in the fact that some drinking water quality experts in water companies havethe firm view that sampling public buildings would increase the investigative work

they have to carry out in response to the results of coliform indicator tests in

particular. Another factor behind this concern is the fact that the European Drinking

Water Directive at the moment only recognises the responsibility of owners for

building water system maintenance in domestic properties, not in public buildings.

94

95

96

97

98

99

100

2001 2002 2003 2004 2005

Year

%M

eetingStandard

25 g/l

10 g/l


10/70


5

In 2005 the Inspectorate asked all companies in England and Wales to identify the

samples in their programmes collected from public buildings. All but five companies

reported they had collected samples from public buildings. Overall about 3% of

nearly 142,000 samples were from public buildings although some companies

sampled at a higher rate (maximum 10%). From analysis of this information I canreport that only 1 in 218 public building samples required investigative work

compared to 1 in 221 samples from domestic properties. There is therefore no

evidence to support the undue burden argument of water companies and my

Inspectors will be checking to ensure that all companies sample a similar and

reasonable proportion of public buildings in future.

Events affecting drinking water quality in 2005In my regional reports I give details of events and incidents notified in 2005. In

England and Wales as a whole a total of 92 incidents were notified in 2005 ascompared to 89 incidents in 2004. Of the 92 incidents in 2005, 8 were in Wales.

The details of each of these incidents are of particular interest to local authorities

and health professionals therefore I have again this year published such information

(in my regional reports) together with the findings of the investigating Inspector.

Even in the most well run of companies incidents will happen. What matters is how

well a company minimises both the risk of occurrence and the consequences of

incidents acting to protect public health at all times. Information about incidents is,

I believe, of particular benefit to the work of the Consumer Council for Water. It also

serves as a basis for dialogue and learning in local drinking water quality and health

professional forums.In 2005, in both England and Wales, health authorities reported a higher than usual

number of cases of cryptosporidiosis in the autumn. A number of outbreaks were

recognised, one in the north of Wales and two in the south of England and outbreak

control teams were established promptly. Longer term surveillance by the Health

Protection Agency has shown that cases of cryptosporidiosis due to the human strain

Cryptosporidium hominisare more frequent in autumn than at other times of the

year whereas the well recorded spring time peak of cases due to Cryptosporidium

parvum(animal origin) has virtually disappeared. On the basis of available information

I wrote to water companies in December 2005 (Information Letter 17/2005) on the

subject of their cryptosporidiumrisk assessments (a regulatory requirement). I asked

companies to provide the Inspectorate with updated risk assessments for surface

water sources by the end of April 2006. Additionally and in the same time frame, the

Inspectorate commissioned a report from the Health Protection Agency to formally

update health surveillance information and knowledge of the organism since the

publication in 1998 of the Third Report of the Expert Group on Cryptosporidiumin

Water Supplies. These actions will contribute to the evidence I require to give my

advice later this year about the adequacy of the arrangements in place to safeguard

consumers from waterborne outbreaks of cryptosporidiosis.


11/70

Drinking water 2005

6

I felt it was in the public interest for the Inspectorate to carry out very extensive and

thorough investigations of the two cryptosporidiosis incidents potentially linked by

early descriptive epidemiology to a source of water for public water supplies.

Amongst their many tasks my Inspectors took statements from consumers in North

Wales diagnosed as suffering from cryptosporidiosis and these accounts are atestament to the severity and consequences of the illness suffered.

In my regional reports for Wales and the Southern region in England I describe the

outbreaks in more detail. I am pleased to record that the water companies concerned

have co-operated fully with the Inspectorates investigations, more importantly they

worked closely with local health officials to help bring both outbreaks under control

as quickly as practicable. The Inspectorates findings and conclusions regarding these

incidents are not included in this report because at the time of its preparation the

offence of supplying water unfit for human consumption was under consideration.

Water safety plan approach

In Part 2 of this report I outline best practice regarding drinking water safety and

present a view of the performance of each water company, and the industry as a

whole, using a basket of measures set within the WHOs water safety framework.

I hope this picture will result in a more informed dialogue between all who have a

part to play in the safe management of our drinking water supplies. I have also

published details of the data used and the method of calculation of each of the

measures.

During the year I observed that it is not uncommon for media reporting of commentsmade by opinion formers, academics and advocates for the environment to give the

false impression that a contaminant in a natural water body equals poison pouring

out of consumers taps everywhere.

Similarly discussions about the importance of protecting water sources and the

undesirability, as a matter of principle, of end of pipe solutions (water treatment)

often revealed misunderstandings about how the safety of drinking water quality is

assured, particularly regarding the extent and scope of treatment applied to drinking

water for particular substances. Noting this gap in knowledge I have this year

published, in Part 2 of this report, details of the water treatment in place at the end

of 2005, and that planned for the future. What is most evident from this information

is the very different challenge faced by each of the companies. This demonstrates one

of the important principles of the WHO water safety plan approach, namely that each

individual water supply chain requires a comprehensive risk assessment and a well

communicated risk management strategy.


12/70


7

Training drinking water professionals for the futureChanges in the industry over the past 15 years have led to discussions and a

growing concern about the best means of developing drinking water professionals

to equip them with the full range of skills and knowledge required to ensure watersupplies are managed to protect public health. I am pleased therefore to announce

that the Inspectorate has taken steps to address this concern by working in

partnership with the University of Surrey to develop and deliver a flexible programme

of either full time or part time study leading to an internationally accredited

postgraduate qualification for engineers and scientists. Full details are published as

an annex in Part 2 of this report, the course is available for the first time in 2006 and

I commend it to the industry.

The duty of everyone to safeguard drinking waterI am very pleased that the new Consumer Council for Water has announced in its

forward programme of work that it will be working closely with the Inspectorate to

ensure that consumers are adequately informed about drinking water quality matters

including their own responsibilities. If something goes wrong with drinking water it

can be something of an automatic reaction of consumers to point the finger of blame

at the water company. However, sometimes the remedy lies rather closer to home. In

2005 companies informed the Inspectorate of various situations which had come to

their attention where the owner had failed to maintain the domestic water systems

inside their buildings.


13/70

Drinking water 2005

8

The degree of neglect illustrated in the photographs below is regrettably neither

atypical nor uncommon. It is in everyones interest that consumers are supported by

appropriate information and advice about how to look after their domestic water

supply. The Inspectorate has been working with WHO and others to develop simple

risk assessment protocols for use by those responsible for domestic water systems inpublic and commercial buildings and for private for private water supplies.

Consequences of uncovered tanks Consequences of inappropriate tank

location

Professor Jeni Colbourne MBE

Chief Inspector of Drinking Water


14/70


9

IntroductionThe Chief Inspectors report Drinking Water 2005 on the quality of drinking water in

England and Wales is presented in a series of publications.

Part 1 Drinking water standards and science provides information on how drinking

water quality is measured and regulated. It sets out the responsibilities of the

Drinking Water Inspectorate and various other organisations in the protection of

water and public health. It also explains how to resolve issues with drinking water

quality and gives details of the latest drinking water science and research

programme.

Part 2 Drinking water safety describes best practice on drinking water safety and

sets out the performance of the industry and individual companies in these terms.

This document is one of a series of regional reports on drinking water quality

comprising Part 3 Regional reports.

In total there are seven regional reports designed to meet the needs of local

authorities, consumers through their Consumer Council for Water (CCWater). The

Consumer Council for Water is made up of regional Committees, the boundaries of

which determine the scope of each report as shown on the map below.


15/70

Drinking water 2005

10

The regional reports follow the above boundaries and are designed to provide

information on drinking water quality which is focussed on local issues and written

in a way to make the science and regulations easily accessible.

The report provides an insight into a number of aspects of drinking water quality.Not only does it inform on the outcome of tests taken for microbiological, physical

and chemical parameters in the region and the reasons for any failures to meet

standards, but it also uses maps to show variations in drinking water quality for iron,

manganese, lead and fluoride across the region. Additionally an overview of incidents

occurring in the region, their cause and outcome, is given with a view to sharing

learning. We include topics of local interest, chosen because they illustrate an

interesting event or development or that they explain the background to a local issue

related to water quality. We report on the technical audit work of our inspectors by

describing the audits carried out in the region and their main findings. The contact

that consumers have with their water companies on the subject of drinking waterquality is also presented. Finally, the regional reports serve as a means for us share

the feedback received from local authorities and health professionals.

This year, for the first time, the Inspectorate will distribute the reports more widely by

providing libraries in England and Wales with copies as well as ensuring that they can

be accessed from the Inspectorates website at http://www.dwi.gov.uk


16/70


11


Key facts

Population suppliedAmount of water supplied l/day

Number of local authorities

Local Health Boards

2,822,400863 million

22

22

Treatment worksService reservoirsWater supply zonesLength of mains pipe (km)

9964910426,988

Area of supply

Anglesey, Blaenau Gwent, Bridgend, Caerphilly,Cardiff, Cardiganshire, Carmarthenshire, Conwy,Denbighshire, Flintshire, Gwynedd, Merthyr Tydfil,Monmouthshire, Neath and Port Talbot, Newport,Pembrokeshire, Powys, Rhondda Cynon Taff, Swansea,Torfaen, Vale of Glamorgan, Wrexham County

Borough.

Water composition

Surface sourcesGround water sourcesMixed sources

93%6%1%


17/70

Drinking water 2005

12

Water sourcesFour water companies supply drinking water in Wales: Albion Water (ALB), Dee

Valley Water (DVW), Dwr Cymru Welsh Water (DWR) and Severn Trent Water (SVT).

Severn Trent Water mainly supplies consumers in England but is included here asit also supplies water to consumers in the central eastern area of Wales. Albion

Water supplies a single large industrial customer (Shotton Paper Company) in north

east Wales.

Much of the water supplied in the region is surface water (93%) abstracted from

rivers such as the Dee, Severn, Towy and Wye. The upland areas of Wales are

important catchments for the water resources in the region.Water is drawn from

many reservoirs including the Alwen, Elan, Taff Fechan and Vyrnwysome of which

also supply consumers in England. For example the Elan reservoir supplies the city

of Birmingham and the Vyrnwy reservoir supplies consumers in North Cheshireand Merseyside.

Across the region a small proportion (6%) of water supplies are from groundwater

sources and a further small proportion (1%) of supplies are from a mixture of surface

and groundwater.

In Wales there are large rural areas without a public water supply. For example,

Powys County Council is aware of over 5,500 private water supplies, Cyngor Sir

Ceredigion knows of 2,400 and Denbighshire has details of 1,170. Responsibility for

checking the safety and sufficiency of private water supplies in Wales rests with the

local authorities. The role of the Drinking Water Inspectorate in respect of privatesupplies is to provide expert technical advice to the National Assembly for Wales, local

authorities and owners of private water supplies. A consultation will be taking place

during the summer of 2006 on the future form of private water supply regulation.

Further information can be found at http://www.defra.gov.uk

Drinking water quality testingThroughout 2005, water companies sampled drinking water across the region to test

for compliance with the standards in the Water Supply (Water Quality) Regulations

2001. More than one third of the tests were carried out on drinking water drawnfrom consumers taps selected at random.For monitoring purposes, company water

supply areas are divided into zones based on population (maximum 100,000).

Generally zones are sampled at consumer taps with the number of required tests

being greatest in zones with larger populations. Other sample locations are water

treatment works and treated water (service) reservoirs. Collectively the four water

companies carried out a total of 356,944 tests during 2005. Only 146of thesetests

failed to meet the standards set down in the regulations.


18/70


13

Table 3.1.1 Number of tests carried out by companies in the region

Place of samplingAlbionWater

Dee ValleyWater

Dw rCymruWelsh

Water

SevernTrentWater

Total

Water treatment works 0

(0)

6,943

(4)

56,966

(74)

6,243

(7)

70,152

(85)

Service reservoirs 0

(0)

9,661

(30)

129,335

(545)

25,380

(73)

164,376

(648)

Consumers taps (zones) 600

(1)

8,062

(15)

111,324

(83)

2,430

(5)

122,416

(104)

Number of tests percompany

600 24,666 297,625 34,053 356,944

Estimate of population 400 160,000 2,609,000 53,000 2,822,400

Note: Numbers in brackets reflect the number of works, reservoirs or zones operated by that

company in 2005 in Wales. Some companies are permitted to carry out some tests on samplestaken from supply points rather than from consumers taps.

The regulations require companies to test for specified parameters at prescribed

frequencies. Most of the testing is for parameters with European or National

standards (mandatory quality standards), and these results are discussed here. Water

companies are also required by the regulations to test for other indicator parameters

such as ammonium, sulphate and colony counts. A summary of the results of testing

by each company, including the indicator parameters can be found on the DWI

website and on the CD accompanying this report.

Drinking water quality resultsThe key water quality results for Wales are presented in two tables, one showing

results for microbiological parameters (Table 3.1.2), the other dealing with

chemical and physical parameters (Table 3.1.4).The microbiological quality of

water is discussed first. Companies report all results of tests on a monthly basis

to the Inspectorate.


19/70

Drinking water 2005

14

Microbiological quality

Table 3.1.2: Microbiological parameters

ParameterCurrent

StandardTotal number

of tests

No. of tests

not meetingthe standard

Additional Information

Water leaving water treatment works

E.coli 0/100ml 8,248 1 DVW (1)

Coliform bacteria 0/100ml 8,247 6 DVW (1), DWR (5)

Cryptosporidium


20/70


15

E.coliat works

In 2005, a total of 8,248 tests at works were carried out by all the companies across

the region. E.coliwas detected in only one sample (DVW). On detecting E.coli,

companies are required to act promptly to protect public health. Their immediateresponse when finding E.coliat a works is to sample again and more widely to

confirm that water being received by consumers is safe. In 2005 these additional tests

gave satisfactory resultsand there were no subsequent E.colifailures in 2005.

Dee Valley Water reported an E.colifailure at Boughton works in August and

Boughton Tower and Pipers Ash reservoir were chlorinated. The company

investigation revealed that two slates were out of position on the water tower roof,

the slates were repaired and the tower roof is now inspected on a daily basis. All

additional samples taken in response were satisfactory.

Table 3.1.3 Detection of E.coli and Enterococci at treatment works, service reservoirsand consumers taps

E.coliin waterleaving

treatmentworks

E.coliin waterleaving service

reservoirs

E.coliatconsumers

taps

Enterococci atconsumers

taps

Albion Water 0/0 0/0 0/12 0/4

Dee Valley Water 1/781 0/1,610 0/496 0/94

Dw r Cymru Welsh Water 0/6,594 0/21,502 1/7,191 0/583

Severn Trent Water 0/873 0/4,230 0/147 0/19

Wales overall 1/8,248 0/27,342 1/7,846 0/700

Note: Results are shown as the number of positive tests/the total number of tests.

Coliform bacteria at works

Testing for coliform bacteria gives reassurance that water is being treated adequately

to remove bacterial and viral pathogens. Repeated occurrences of coliform bacteria

in samples at the same works in one year are thus of concern and require action to

be taken.

In 2005, this situation occurred at one works in the region. The Alaw works onAnglesey (DWR) exhibited coliforms in tests on four separate occasions between

31 May and 26 July. The company developed an action plan which included cleaning

the on site contact tank and changing the disinfection process (from chloramination

to chlorination). An initial completion date for all remedial actions was agreed as end

October 2005. Most remedial actions were completed on time, however, the

company reported that the remainder could not be completed before the end of

2005. As a consequence DWI initiated enforcement action and as a result the

company have put in place a legally binding programme of work to be completed by

March 2006. There were no further failures at Alaw works during 2005.


21/70

Drinking water 2005

16

Following two coliform failures in 2004 D wr Cymru Welsh Water committed to a

legally binding improvement programme at Cwellyn (New) works to investigate the

efficiency of the treatment process and take appropriate remedial action to rectify

any deficiencies by 31 March 2006.

Cryptosporidiumat works

The regulations require companies to monitor for this parasite at those works

assessed to be at significant risk. In 2005 monitoring was required to be undertaken

at 18 works (3 DVW, 14 DWR, 1 SVT). All results met the regulatory treatment

standard of


22/70


17

Dwr Cymru Welsh Water took Forest Lodge tank out of service following the

second coliform detection in November. Action taken before return to service

included removing overhanging trees and replacing a UV light. The company

investigated two failures at Earlswood reservoir in July and concluded that lower

than normal residual chlorine levels required correction by use of a chlorine dosingpoint during the summer months. At Cynghordy reservoir the investigation of a single

failure in November identified the potential for ingress and the reservoir was removed

from supply.

Penybont works near Tywyn supplies two reservoirs (Mynydd Bychan & Gwelfor Rd)

and both recorded a coliform failure in 2005. Dwr Cymru Welsh Water has an

improvement programme related to turbidity at the works scheduled for completion

in 2008.In the meantime the method of disinfection will be changed to

chloramination to ensure chlorine residuals can be maintained in distribution.

The Inspectorate has noted that coliform bacteria were found in 18 samples from

service reservoirs in the Wales during the year and this information will inform the

Inspectorates risk based programme of technical audit.

E. coliand Enterococci at consumers taps

A total of 7,846 consumer taps were tested in 2005 for E.coliand one was positive

(DWR). The investigations by the company indicated that the failure was likely to be

due to the customers tap and there was no indication, from information gathered by

the water company, of a faecal contamination event affecting other properties in

these zones.Like E.colithe presence of Enterococci is indicative of faecal contamination and

neither bacterium should be found in any sample. In 2005 the companies carried

out 700 tests for Enterococci at consumers taps. All samples met the standard.

Chemical quality

The Water Quality (Water Supply) Regulations 2001 set out the minimum testing

requirements for all chemical and physical parameters. A summary of the results of

testing by each company, including the results for indicator parameters is provided on

the DWI website and on the CD accompanying this report.

The table and text below set out the results for those parameters where there has

been a failure to meet a European or National standard (mandatory quality

standards). In addition, due to local authority interest, the results of testing for

fluoride, iron, lead, manganese, nitrate, nitrite and pesticides are given.


23/70

Drinking water 2005

18

Table 3.1.4 Chemical and physical parameters

ParameterCurrent

standard

Totalnumberof tests

Number oftests not

meeting the

standard

Additional Information

Aesthetic parameters

colour odour taste

20 mg/l pt/Co

3 at 25C3 at 25C

1,914

2,2752,046

0

23

DWR (2)DWR (3)

Aluminium 200 g/l 2,105 2 DWR (2)

Bromate 10 g/l 715 1 DWR (1)

Fluoride 1.5 mg/l 689 0

Iron 200 g/l 2,674 11 DWR (11)

Lead (current standard)

Lead (future standard)

25 g/l

10 g/l

702

702

2

6

DWR (1) DVW (1)

Further informationincluding a map andgraph can be foundwith the text below

Manganese 50 g/l 2,168 7 DWR (7)

Nitrate 50 mg/l 996 0

Nitrite 0.5 mg/l 999 3 DWR (3)

Pesticides Total 0.5 g/l 689 0

Pesticide Individual(see note 3) 0.1 g/l 31,965 1 Mecoprop DWR (1)

pH (Hydrogen Ion) 6.5 10.0 1,968 1 DWR (1)

Trihalomethanes Total 100 g/l 703 2 DWR (2)

Turbidity 4 NTU 2,033 1 DWR (1)

Notes:

1. For summary details of all tests undertaken by each water company refer to the DWIwebsite or the CD accompanying this report.

2. For comparison, 1 mg/l is one part in a million, 1 g/l is one part in a thousand million.

3. A further 3,207tests were done for aldrin, dieldrin, heptachlor, heptachlor epoxide, all ofwhich met the relevant standard.

Aluminium

Aluminium can occur naturally in some drinking water sources. Also, aluminium

based water treatment chemicals may be used at surface water works to aid the

process of filtration.


24/70


19

In 2005 a total of 2,105 samples were tested for aluminium in Wales. Dee Valley

Water, Severn Trent Water and Albion Water achieved 100% compliance with the

aluminium standard. Just two tests (DWR) exceeded the standard and none of these

were found to be related to process control at the works. Both failures arose from

localised disturbance of deposits accumulated in the distribution network and otherstandards (iron or manganese) were exceeded at the same time (see discussion under

Water quality in distribution).

Bromate

Normally bromate is only formed in drinking water when bromide is present in

surface water treated with ozone. The process of chlorination may also produce

bromate, for example, through the use of sodium hypochlorite solution containing

bromide or when chlorine is generated on site by electrolysis. In the past three years,

companies have put in place control measures aimed at meeting the standard of 10

g/l, which was new in 2004.

In Wales, out of a total of 715 tests, the standard was exceeded on one occasion in

2005. Dwr Cymru Welsh Water linked the failure in the Capel Dewi zone in October

to an error relating to the treatment chemical at Capel Dewi works (Carmarthen).

The contractor used by the Company had subcontracted to another supplier but

had failed to specify the correct grade of hypochlorite solution. The contractor has

since corrected their records, no further failures have occurred in the zone.

Fluoride

Traces of fluoride may occur naturally in many water sources, particularly ingroundwaters. Figure 3.1.5 provides information on the average fluoride level

recorded in each zone (2004/05 data combined) in Wales. Consumers should obtain

specific information on the level of fluoride in the drinking water supply to their

home or workplace from theirwater company.

Fluoride is not removed by conventional water treatment. Some companies fluoridate

water supplies at the request of the local health authority as a protection against

tooth decay. The Inspectorate is not aware of any fluoridation schemes in Wales. In

2005, all 689 tests for fluoride taken across the region met the regulatory standard

(1.5 mg/l). For more information on fluoridation please refer to the DWI websitehttp://www.dwi.gov.uk


25/70

Drinking water 2005

20

Figure 3.1.5 Average fluoride levels in zones for 2004/05

Lead

The pipe connecting a property to the water company main, together with internal

plumbing, is the most common source of lead in drinking water. The extent of leadpick up depends on various factors; temperature, acidity (pH), water hardness, the

length of pipe and the time that water is left to stand in the pipe (stagnation) before

it is drawn off. Properties built or renovated since 1970 are unlikely to have lead

pipes and since 1990 water companies have opportunistically replaced many service

connections as part of their water distribution maintenance programmes. For

example, at least 445,000 service pipes were replaced between 1991 and 1994

in Wales and England.


26/70


21

In 1996 the World Health Organisation (WHO) tightened its guideline for lead in

drinking water because lead can accumulate in the body and this can give rise to

adverse neurological health effects in young children. When setting the new

guideline of 10 g/l, WHO recognised that the permanent solution, removal of lead

pipes, would take time and money to achieve. The view of WHO was that otherpractical measures (water treatment) should be introduced in the interim. This WHO

advice was adopted formally in Europe through the 1998 Drinking Water Directive,

which set an interim standard of 25 g/l (December 2003) and a final standard of

10 g/l (to become effective in 2013). In the UK it was determined that phosphate

dosing was the most cost effective way of treating the water and making it less likely

to dissolve lead from pipes and solder.

Table 3.1.6 Percentage of lead tests meeting the 25 g/l standard from 2001 to 2005

2001 2002 2003 2004 2005

Albion Water 100% 100% 100% 100% 100%

Dee Valley Water 98.65% 100% 98.72% 99.23% 99.24%

Dw r Cymru Welsh Water 98.79% 99.41% 99.88% 100% 99.85%

Severn Trent Water 94.89% 95.98% 99.32% 99.72% 99.65%

Note: The 25 g/l standard was not a regulatory requirement until 25 December 2003

Note: Figures are calculated on whole company data and may include results relating toconsumers in England, there were no lead failures in the area of Wales supplied by SVT in2005

In Wales, good progress has been made by each company towards meeting the new

standards. The improving trend for the region can be seen in Figure 3.1.7. Looking

towards the future and based on monitoring during 2005 it appears that less than

one percent of drinking water taps in properties in Wales are likely to exhibit lead at

levels greater than the standard of 10 g/l.


27/70

Drinking water 2005

22

Figure 3.1.7 Percentage of lead tests meeting the 25 g/l standard from 2001 to 2005

90

92

94

96

98

100

2001 2002 2003 2004 2005

Year

%M

eetingStandard

25 g/l 10 g/l

The companies have completed their initial programmes of water treatment measures

and during 2005 all companies have been optimising phosphate dosing levels. The

area now covered by schemes in the region is illustrated in figure 3.1.8. The scheme

for additional treatment to reduce lead levels from the raw water at Talybont works is

due for completion in 2009.The extent and location of failures reported by

companies as part of their regulatory sampling programme in both 2004 and 2005 isalso shown on the map. It is important to realise that the risk of consumer exposure

to lead is limited to only those properties with lead pipes. Although many properties

will not yet have been sampled as part of the companies regulatory monitoring

programmes, consumers can request that their water company take a sample from

their home if they suspect lead may be present. In 2005 Dee Valley Water reported

103 consumer requests of this nature.

Meeting the lead standard is a complex matter because not all owners of buildings

will choose to replace lead pipes, even when notified of an adverse test result by their

water company. Also some lead in drinking water is due to the use of lead solder oncopper pipes and fittings (despite the fact that the use of lead solder for drinking

water installations was banned in the early 1970s). Brass fittings provide a further

source of lead in some buildings.


28/70


23

Figure 3.1.8 Maps showing the distribution of lead results above the existing and

future standard, along with the extent of zones covered by an improvement

programme


29/70

Drinking water 2005

24

As part of the regulatory programme of tap sampling, water companies notify

local authorities of the location of every sample containing lead above 25 g/l.

The Inspectorate recommends that local authorities actively review this information

to identify hot spots in their area where additional measures may be required to

reduce exposure to lead. For example, there is asmall clusterof elevated lead resultsnearWrexham. Locations of particular interest to local authorities might be schools

and other similar public buildings or social housing. Most water companies will

replace their part of a service pipe when the building owner indicates they wish

to remove the domestic lead plumbing. This good practice is something that local

authorities may wish to promote and the Inspectorate encourages companies and

local and health authorities to develop joint communication programmes in hot

spot areas.

Nitrate and nitrite

In 2005, all tests for nitrate met the standard (50 mg/l).Nitrate occurs naturally in all

source waters due to the natural decay of vegetable material in soil. Nitrogenous

fertilisers used on arable farmland are a significant source of nitrate in groundwater.

Rainfall washes nitrate from the soil in to lakes, rivers and streams. Nitrate levels can

be reducedby water treatment or by blending with another, low nitrate, water

source.

Nitrite may be formed when chloramine is used as the residual disinfectant to

maintain the microbiological quality in the distribution network. The formation of

nitrite is controlled by careful optimisation of the disinfection process. Only a few

supplies in the region are chloraminated. Nitrite can also form in samples of water,after collection and before analysis, especially if the sample is not kept cool.

In 2005, three of the999tests carried out across the region for nitrite failed the

standard (DWR 3). Two samples taken on the same day in July 2005 from the North

and the East Anglesey zones breached the nitrite standard. Both these zones are

supplied by Alaw works where chloramination is used for residual disinfection. The

investigation found a wider problem particularly in the more remote parts of the

distribution system such asAmlwch town. Advice obtained by the company from the

North Wales Health Board was reassuring as regards the level of nitrite found being

low in relation to the World Health Organisations health related guideline for a lifetimes consumption. In September the company changed the residual disinfectant

from chloramine to chlorine at the Alaw works and this action together with flushing

of the distribution system led to a marked improvement in the situation. These

compliance failures were associated with a general deterioration in water quality

supplied by Alaw works (see also sections on coliform and trihalomethane failures)

which was notified to the Inspectorate and initially regarded as a water quality

incident. The third failure of the nitrite standard in September was also in the North

Anglesey zone. This zone is also served by a supply from the Cefni works, the

chloramination dose at this works was modified and subsequent sampling has given

satisfactory results.


30/70


25

Pesticides and related products

This group of substances generically called pesticides, includes many organic

chemicals with a wide range of uses such as weed killers, insecticides and fungicides.

Water sources may contain traces of pesticide residues as a result of agricultural use(pest control on crops) and non-agricultural use (herbicide for weed control on

highways etc.). Water companies are required to assess the risk to drinking water

from pesticide use in their catchments and then test for those individual pesticides

that might be present. There are standards for individual pesticides as well as a

standard for the sum of all the pesticides. The standards are set with a wide safety

margin. Many works in the region now have treatment capable of removing most

pesticides in general use.Companies are expected to keep up to date their list of

pesticides used in the catchment for each source.

In 2005, none of the 689 tests in the region exceeded the standard for total

pesticides. Likewise there was 100% compliance (3207 tests) for the four pesticides

with a standard of 0.03 g/l. Out of a total of 31,965 tests for individual pesticides

(with a standard of 0.10 g/l) just oneexceeded the standard for mecoprop (DWR).

When pesticides are first detected, water companies take action to protect

consumers, enhance their monitoring programme and where appropriate pass details

to the Environment Agency.

In December the herbicide mecoprop was detected at a level 0.12 g/l in a

consumers tap sample taken in the Malpas/Caerleon/Cwmbran zone. Mecoprop

was also detected in the raw water at Court Farm works which supplies the zoneat the same time. No previous or subsequent samples have shown mecoprop

concentrations above the standard. The Inspectorate has sought details from the

company about the control measures it has put in place for management of pesticide

use in the catchment to this works.

pH (Hydrogen ion)

pH is a measure of the acidity of the water. Where water is supplied from upland

areas the water naturally picks up iron and humic acids from the peaty soils, resulting

in slightly acidic water with a low pH, which is commonly described as soft water.

Such water has an increased potential to corrode iron pipes and leach material fromcement lined mains. Acidity can also be affected when water is artificially softened by

a treatment device in a consumers property.

In Wales only one test out of a total of 1,968 tests exceeded the standard. A pH of

6.46 was recorded by Dwr Cymru Welsh water in the Strata Florida zone in March.

Improvements to the treatment at the Strata Florida works, including carbon dioxide

dosing, will secure compliance with the pH standard in future years. This scheme is

scheduled for completion in 2006.


31/70

Drinking water 2005

26

Trihalomethanes

Trihalomethanes (THMs) arise when chlorine is added to water containing naturally

occurring organic substances. Treatment processes are optimised by water companies

to minimise their production. For more information on THMs and how the level ofTHMs is controlled by water companies please refer to the DWI website.

In 2005, out of 703 tests, only two (DWR) exceeded the standard in Wales. Dee

ValleyWater, Severn Trent Water, and AlbionWater all achieved 100% compliance.

A sample taken on 17August in the North Anglesey zone gave a result of 101.8 g/l.

The sample was taken in the area supplied by Alaw water treatment works and wider

sampling indicated elevated levels of THMs throughout the distribution system

supplied by the works. The company had changed the disinfection process (from

chloramination to chlorination) in response to coliform and nitrite failures (discussed

in earlier sections) anddid not anticipatethe need to also adjust the coagulationdose in light of their knowledge of the raw water quality and the potential for

THM formation. Once this was done, there were no subsequent failures for THM in

this zone.

A sample taken on 5August in the Llyswen zone gave a result of 103.24 g/l and

sampling found elevated THM levels more widely at the Llyswen works and in

distribution. The company realised that it needed to put in place operational triggers

and enhanced monitoring so it was better placed to manage the impact of the

variable raw water quality on the disinfection process.

Water quality in distributionThetwo chemical parameters with the highest number of failures across the region

are iron and manganese. These substances may be present naturally in raw water,

iron compounds may be added as part of water treatment or it can be released as a

consequence of the corrosion of iron mains. The most severe problems tend to be

where the distribution network contains a large proportion of old cast iron mains.

Effective water treatment reduces iron and manganese at source, but if treatment is

not effective, iron and manganese may collect in distribution pipes. When these

deposits are disturbed, they may cause orange-brown or black discolouration of the

water. Elevated levels of iron and manganese can also result in breaches of theturbidity standard.


32/70


27

Table 3.1.9 Compliance by company with the standards for iron, manganese and

turbidity

Iron Manganese Turbidity

Albion Water 100% 100% 100%Dee Valley Water 100% 100% 100%

Dw r Cymru Welsh Water 99.40% 99.83% 99.98%

Severn Trent Water 99.70% 99.96% 99.98%

Wales overall 98.76% 99.85% 99.98%

Note: Figures are calculated on whole company data and may include results relating toconsumers in England. For more information on % parameter compliance please refer to theCD accompanying this report.

Figure 3.1.10 shows the distribution of iron and manganese failures in zones across

Wales. The map highlights some areas where the standard for iron (200 g/l) wasexceeded on more than one occasion in 2005.

Figure 3.1.10Map showing the distribution of failures, along with the extent of

zones covered by an improvement programme


33/70

Drinking water 2005

28

The map also shows the areas where the water companies arecommitted to a legally

binding programme of improvement work under section 19 of the Water Industry

Act 1991, where the work was in progress in 2005, or is still planned for the future.

Dwr Cymru WelshWater are yet to complete their long term programmes of work to

replace or refurbish cast iron mains. Table 3.1.11 below summarises the progressmade with these programmes during 2005 and shows the work which remains

outstanding.

Table 3.1.11 Progress with Section 19 distribution system improvement programmes

Length ofmain replacedor refurbished

in 2005

Length ofmain still to

be replaced orrefurbished

Renovationcompleted

Completiondue

Dee Valley Water 0.1 km None Sep 2004 N/A

Dw r Cymru Welsh Water 333.7 km 2077.1 km N/A March 2010

Severn Trent WaterNone (from

Feb 2005)None Feb 2005 N/A

Wales overall 333.8 km 2077.1 km

The lengths given here relate to zones which are wholly or mainly in Wales.

Dee Valley Water and Severn Trent Water have now completed their strategic

programmes. Dwr Cymru Welsh Water continued to make satisfactory progress

against targetsduring 2005.The improving trend between 1997 to 2005 is illustrated

in the graph (Figure 3.1.12).

Figure 3.1.12 Trends in operational performance

98.5

99.0

99.5

100.0

1997 1998 1999 2000 2001 2002 2003 2004 2005

Index(%)

Dee Valley Dwr Cymru Severn Trent

Note: Trends relate to results for three parameters iron, manganese and turbidity. Only

companies with more than five zones are shown.


34/70


29

As can be seen from figure 3.1.10, all of the failures that occurred in 2005 are in

areas where the company is already carrying out a programme of work.

Dwr Cymru Welsh Water reported 11 iron failures and seven manganese failures

in Wales. The company confirmed that a number of these failures were likely tobe related to ongoing improvement works (e.g. Builth and Bryncoch zones). The

majority were single failures in a zone, but the following zones reported more than

one failure.

In Llandudno/Colwyn zone in January the results of a sample failed several standards

(aluminium, iron, manganese and turbidity). Dwr Cymru Welsh Water flushed the

local main to remove a build up of loose deposits and subsequent samples were

satisfactory. A routine fortnightly flushing programme has been put in place. An iron

failure in the Holywell/Mold zone (DWR) in July also coincided with an aluminium

failure. Again the company flushed the local main to remove loose deposits.

Two iron failures were reported in the Rhymney/Bargoed zone (DWR). One in August

was probably related to improvement work on the mains in the zone but the one in

January was localised to a section of main serving a single property. The company has

confirmed that approximately 100m of main will be replaced. The Maerdy Porth zone

had two iron failures in Februaryand is included for renovation as part of the Section

19 improvement programme.

A failure of iron was reported from the Elan zone in April in an area where the mains

have already been refurbished. The company consider that the poor condition of the

Bwlch Sarnau reservoir is the cause. The reservoir is scheduled to be abandoned andthere should be no further problems thereafter.

The Cray/Clydach zone failed the standard for manganese on five separate occasions

during 2005. The water mains in this area are known to be in generally poor

condition containing manganese deposits which are prone to re-suspension at times

of peak demand or as a result of any disturbance during planned work or a burst

main. This area has experienced a number of significant discolouration incidents in

recent years. This zone has been prioritised for mains renovation involving both

refurbishment and replacement of trunk mains and feeder mains throughout the

Cray system. This strategic project has been ongoing for the past two years and is

scheduled for completion in the autumn of 2006.

Aesthetic parameters

Consumers expect their drinking water to be not only safe to drink, but also clear

with no discernible taste or odour. In recognition of this the regulations stipulate

national standards for colour, odour and taste. In 2005, all tests in the region met

the standard with the following exceptions.


35/70

Drinking water 2005

30

Dwr Cymru Welsh Water reported three samples that failed the standard for taste

and two of these samples also failed the standard for odour during 2005. Samples

were taken from three separate supply zones between July and September. None of

the failures could be related to any water source or water treatment problem and

further monitoring gave satisfactory results. One of the samples was from a zoneserved by Felindre works where there is an improvement programme for taste and

odour. The construction phase of this work is scheduled for completion by the end

of December 2006.

Consumer perceptions of drinking water qualityWhen consumers have a question or a concern about drinking water quality their first

point of contact is the water company. The Inspectorate held a workshop with

companies in the autumn of 2005 to develop definitions for drinking water quality

consumer contacts. These definitions and guidance on recording and reportingconsumer contacts are contained in Information Letter 1/2006

(http://www.dwi.gov.uk). Dee Valley Water was able to provide the Inspectorate with

the full range of consumer contact data for 2005 and this is summarized in

table 3.1.13. The data provided by the other companies was incomplete therefore

figures in table 3.1.13 are estimates made by the Inspectorate drawing on overall

industry figures.

In line with published evidence, consumer perceptions in Wales are very strongly

influenced by the appearance of their drinking water with such contacts being more

than half of the total across the country. This confirms the importance of work being

done to identify the causes and remedies for discoloured water (see section on WaterQuality in Distribution).

Table 3.1.13 Summary of consumer contacts about drinking water quality in 2005

Appearance

Tasteand

odour

Reportof

illness

Water

quality

concern

Information

request

Total

number

ofcontacts

Contactrate

per1,0

00

population

Albion None None None None None None n/a

Dee Valley Water 48% 15% 1% 13% 23% 774 3.29

Dw r Cymru Welsh Water 83% 12% 2% (2%) (1%) (17,042) (6.26)

Severn Trent Water 54% 32% (None) 1% (13%) (112) (2.78)

Wales overall 14,539 2,165 (417) (514) (293) (17,928) (5.98)

Note: figures in brackets are estimated from industry average. The figures for DVW, DWR,SVT are for consumers in Wales only


36/70


31

The poor condition of water mains is not the only visual stimulus impacting on

consumer perceptions in Wales because 16% of all appearance contacts in 2005

related to white water events which happen when air is entrained in water by pumps.

The cause of white water receives much less attention yet it can have a pronounced

impact on consumer perceptions. For example, out of the 302 appearance contacts

received in 2005 from one zone operated by Dwr Cymru Welsh Water 151 (50%)

were reports of white water and in one zone operated by Dee Valley Water 22 (38%)

of appearance contacts were about white water. The Inspectorate believes companies

can and should do more to identify the root cause of white water events and take

steps to prevent them.

There were 608 contacts about chlorine (28% of all taste contacts) in 2005 in Wales.

A recent cross national study of drinking water quality perceptions by the University

of East Anglia found a greater tendency towards chemo phobic attitudes in the UK

than on the continent. The Inspectorate considers that water companies need to takegreater account of these societal attitudes recognising, for example, that consumers

do not perceive chlorine in drinking water as beneficial and fluctuating or higher than

necessary levels of chlorine in drinking water will cause consumers to react adversely.

Access to information is important to consumer confidence. Dee Valley Water and

Dwr Cymru Welsh Water record sending out only 25 drinking water quality testing

reports to consumers in Wales in 2005 (Severn Trent Water did not keep records in

2005). Compared to most companies serving the regions in England, this is a low

figure. Records across the whole water industry show there is a significant demand

for information about drinking water quality amongst consumers. The Inspectorate

believes that the companies serving Wales need to be proactive about ensuring

consumers have access to drinking water quality information, collaborating with the

Consumer Council for Water in Wales on the most effective and preferred methods.

When the response of a company to a consumer contact about drinking water

quality fails to provide the necessary reassurance or remedy then the consumer may

complain directly to the Inspectorate. In 2005, there were 39 customers of the

companies supplying drinking water in Wales who were sufficiently dissatisfied with

the water company to complain to the Inspectorate. The majority (26) of these

customers had experienced discoloured water and seven were reporting an

objectionable taste. As a general rule, when a consumer comes to the Inspectorate itis because the company has not provided the consumer with appropriate, sufficient

or timely information. Consumers who turn to the Inspectorate often display a lack of

trust in their water company and, excluding the very occasional vexatious caller, a

complaint to the Inspectorate should be regarded as a significant opportunity for

learning and improvement by the companys senior management.


37/70

Drinking water 2005

32

Issues of local interestDuring early November 2005, the North Wales Health Protection Team contacted

Dwr Cymru Welsh Water (DWR) to inform the company of an increase in cases of

cryptosporidiosis in the Gwynedd and South Anglesey area. The water company wasasked to check the operation of treatment works supplying the area and to confirm

whether those cases so far recognised received the same water supply. At this time the

company began continuous monitoring of the water supply for Cryptosporidium. The

geographical analysis of cases revealed that the vast majority received a water supply

derived from the Llyn Cwellyn source treated at Cwellyn water treatment works. The

Outbreak Control Team (OCT) chaired by the National Health Protection Service for

Wales (NHPS) took the decision to issue boil water advice to all 70,000 consumers

supplied from Cwellyn WTW on 29 November 2005. This advice remained in place for

eight weeks until 30 January 2006. Cwellyn works remained in supply during the

outbreak. The company installed additional ultraviolet treatment at Cwellyn workswhich was commissioned in early January 2006.

Environmental investigations carried out by the Environment Agency confirmed a

number of sewage inputs to Llyn Cwellyn and samples taken from the lake and the

water supplied from Cwellyn works contained Cryptosporidium hominis. The OCT

studies found that between 1 October 2005 and 31 January 2006 there were 214

cases of Cryptosporidiosis hominisinfection confirmed by the Cryptosporidium

Reference Unit (CRU) in residents of Gwynedd and South Anglesey.

The Inspectorate carried out a thorough investigation into the circumstances of this

incident which was very extensive and included site visits. Inspectors took statementsfrom consumers diagnosed as suffering from cryptosporidiosis and from the companys

staff and contractors responsible for water supply management decisions and the

operation of the works respectively. Information relating to the testing of water and

patient samples was also formally obtained from environmental and medical scientists.

The Inspectorates findings and conclusions regarding this incident is not included in

this report because at the time of its preparation the offence of supplying water unfit

for human consumption was under consideration.

As regards the learning from this outbreak and other outbreaks in England in 2005,

the Inspectorate issued an information letter (IL 17/2005) to all water companies inDecember 2005 asking them to review all cryptosporidiumrisk assessments for surface

water derived supplies and to submit their revised risk assessments (a regulatory

requirement) to the Inspectorate by 30 April 2006. Additionally and in the same time

frame, the Inspectorate commissioned a report from the Health Protection Agency to

update longer term health surveillance data and knowledge about the organism since

the publication in 1999 of the Third Report of the Expert Group on Cryptosporidiumin

Water Supplies. These actions will contribute to the evidence required for the Chief

Inspector of Drinking Water to give advice later this year about the adequacy of the

current arrangements for safeguarding consumers from waterborne outbreaks of

cryptosporidiosis.


38/70


33

Incidents in 2005The companies in Wales notified the Inspectorate of 28 events during 2005. The

Inspectorate classified eight as incidents requiring a comprehensive report from the

company and a full investigation by the Inspectorate as compared to 11 in 2004.

Table 3.1.14 Water Quality Events in the region in 2005

Number of events notified Number classed as incidents

Albion Water 0 0

Dee Valley Water 1 0

Dw r Cymru Welsh Water 27 8

Severn Trent Water 0 0

Wales overall 28 8

A summary of the nature, cause and durationof each incident, along with details of

the Inspectorate findings are set out in Annex 3. Most incidents wereof relatively

short duration and the company took action to inform and safeguard consumers and

other stakeholders as appropriate.

Learning points from incidents assessed in 2005 are highlighted by the following

examples:

In September 2004, boil water advice was issued to residents of 13,000 properties

in the areas of Nantyglo, Brynmawr, Blaina, Clydach Valley, Maesygwartha and

parts of Ebbw Vale following evidence that flood water had probably gainedaccess to treated water within Rassau service reservoir supplying the area. A

contributory factor was that the pumps were in standby mode and started

automatically in response to a rise in the water level. The precautionary boil water

advice was endorsed by the health authority and was lifted after two clear sets of

sample results had been obtained. The Inspectorate recommended that the

company reviewed the risk of flooding and the practice of enabling standby

pumps to come on line automatically without any operational oversight. The

company has since changed procedures to the effect that pumping stations are

always isolated when not in use.

In November 2004, routine monitoring found coliforms in the Llandudnodistribution network. In the absence of any evidence of a treatment problem the

company carried out flushing of the distribution system and boosted the level of

chlorine residual, however these actions resulted in 29 consumer complaints, 18

about objectionable levels of chlorine in the water. Other consumers were caused

concern by articles about the situation appearing in the local press. The

Inspectorate was critical of the companys strategy of managing the incident,

namely changing the residual disinfectant regime without first identifying the

means to control the concentration to an acceptable and stable level. The

Inspectorate recommended the implementation of a more robust and effective

residual chlorine strategy and improved control and monitoring systems.


39/70

Drinking water 2005

34

The company has since changed the operation of the Bryn Cowlyd works,

optimizing ozonation to reduce chlorine demand generating a stable chlorine

residual with the result that there have been no further coliform failures in

distribution or consumer complaints.

Starting in late August 2005, consumers living in Swansea, the Gower and partsof Carmarthenshire supplied by Bryngwyn works and in rural areas around Brecon

supplied by Portis works, began reporting an earthy or musty taste to the water.

The source for both works is the Usk Reservoir. Sampling detected methyl

isoborneol (MIB) a naturally occurring substance which has an unpleasant taste at

minute concentrations. Over a period of several weeks a total of 150 consumers

reported experiencing the problem. The reservoir last contained significant levels

of MIB in 1999. The Inspectorate found that the company had been slow to

introduce dosing of powdered activated carbon and concluded that the

companys procedures were inadequate for detecting and mitigating a MIB (or

geosmin) event.

The offence of supplying water unfit for human consumption is currently under

consideration by the Inspectorate in connection with one incident which occurred in

2005.

Technical audit activity in the regionDuring 2005 the Inspectorate implemented a new decision making tool for

prioritising its technical audit work. All critical components of the safe management

of drinking water supplies (catchment, water treatment, distribution integrity and

maintenance, sampling, analysis and reporting) are assigned a risk score based oncompany information (results of monitoring, incident assessment, previous audit

findings, consumer complaints etc.). This tool generates a risk ranking for all relevant

water company assets, procedures and practices enabling inspectors to focus their

technical audit work where it can be of greatest benefit.

As a result of this development, there is no longer an annual list of inspection tasks,

instead technical audits are carried out as and when required throughout the year.

Companies and laboratories will be audited less often if they adopt a proactive water

safety plan approach to safeguarding water quality and ensure that their staff are

well trained. Information on the key findings of the Inspectorates technical auditwork in Wales in 2005 is set out in Table 3.1.15.


40/70


35

Table 3.1.15 Summary of the Inspectorate technical audits in Wales (10/5/06)

Site name Audit topic Main findings from audit

Dw r Cymru Welsh Water

Cwellyn WaterTreatment works.

Site audit with specificfocus on the improvementprogramme that resultedfrom enforcement actionin 2004.

Recommendations were made to improveaccuracy of records for issuing of keys toauthorised personnel and regarding theoperation and maintenance of thepressure filters.

Response to 2004recommendations.

Review of actions takenby the company followingrecommendations madeto the company during2004.

Only a small number of actions wereoutstanding. The company is to reporthow these have been completed by30 June 2006.

Sample Audit Trails. Audit trail of fivechemical samples.

Recommendations made to ensure theaccuracy of sampling frequencies.

Sample Audit Trail. Audit trail of onepesticide sample.

Recommendations made regardingimprovements to the calibrationprocedures.

Severn Trent Water

Sample Audit Trails.

Audit trail of eight

chemical samples.

Recommendations made to secure the useof the correct method of analysis forcyanide and the regular calibration ofequipment in respect of pH measurement.Problems also found with the regularity ofsampling for 7 of the 8 parameters.


Audit trail of twopesticide samples.

Improvements required to the schedulingof compliance samples and to analyticalquality control.

Dee Valley Water


Audit trail of five

chemical samples.

Recommendations mostly concern therobustness of the Analytical QualityControl (AQC) system in use in thelaboratory. The Inspectorate stronglyrecommended the company ensured itschosen analytical service providercomplied fully with all regulatoryrequirements.

Albion Water

Sample Audit Trails. Audit trail of twochemical samples.

Satisfactory.


41/70

Drinking water 2005

36

In January 2006, several companies informed the Inspectorate that their analytical

service provider had reported a serious problem with the quality control data

generated by an analyst in one of its laboratories. This affected a number of reported

results for turbidity, hydrogen ion, conductivity and colour for samples analysed

between September and December 2005. The Inspectorate reviewed the informationprovided and concluded that the absence of valid AQC and calibration check data

invalidated these compliance test results and where this was the case, the companies

were required to expunge these test results for their data returns and note the

problem on their public register. The analytical service provider has taken a number

of steps to prevent a recurrence, including improved supervision and re-training

of staff.

Local authority consultation

Section 77 of the Water Act 1991 places a duty on local authorities to keepthemselves informed about the quality of the public water supplies provided to

premises in their area. In February 2006, the Chief Inspector contacted each Local

Authority Environmental Health Service inviting their views on drinking water quality

and the extent to which they are involved in local drinking water quality issues.

In Wales 12 out of a total of 22 local authorities gave their views:

7 indicated that they were satisfiedwith the quality of the public water supply.

5 indicated that they were generally satisfiedwith the quality of the public water

supply.

No local authorities indicated that that they were dissatisfiedwith the quality ofthe public water supply.

11 indicated that they had regular contact with the local water company.

Comments by local authorities included:

We have good liaison with both water companies (DWR & DVW) regarding any

complaints from the public or other problems.

Would like to see more lead communication pipes replaced.

Not sure about the environmental impact of increased phosphate treatment.

Increased concern about Cryptosporidiumfollowing recent problems in a

neighbouring authority.

All twelve local authorities indicated that they take samples of the public water supply

in response to a consumer complaint. Two operate a planned sample programme,

one indicated that their planned programme had been discontinued.

The Inspectorate has set up a formal link with the Chartered Institute of

Environmental Health to identify and support training of local authority personnel on

drinking water quality and regulation. A national steering group met in February

2006 to take this work forward and to provide regular feedback to the Inspectorate.


42/70


37

In partnership with the University of Surrey, the Inspectorate has established an

internationally accredited postgraduate qualification in drinking water supply

management and regulation (details in Annex 4). The modular style course can be

studied on a full or part time basis and covers the full range of knowledge required

by professionals with responsibility for ensuring the supply of safe drinking water.The course is available for the first time in 2006 and is commended to water

companies and local authorities.

Consultation with health professionalsThe Health Protection Agency (HPA) is responsible for health surveillance in both

Wales and England. In England there are 34 Health Protection Units available to

provide advice on health matters at a regional level, with 22 Health Boards fulfilling

the same role in Wales.

In February 2006 the Chief Inspector contacted each Consultant in CommunicableDisease Control and each Director of Public Health in Wales and England inviting

them to comment on their involvement with drinking water matters during 2005.

Information was received from 31 of these medical advisors and all but 3 of these

had been involved in giving drinking water quality health advice during 2005.

Typically health protection teams are responding to requests for advice in their area

on eight occasions in any one year. The three most common reasons for providing

health advice were:

in response to a water quality incident

in support of the local authority environmental health team a query about a specific substance that might be present in drinking water.

The specific situation regarding health advice in Wales cannot be reported here

because none of the medical advisors responded to the consultation.

Overall the consultation exercise revealed that health professionals generally have a

low awareness of the role and expertise of the Drinking Water Inspectorate

suggesting that this topic is not being covered adequately by the water companies in

their routine liaison meetings with local health professionals. All companies serving

consumers in Wales are encouraged to make it a priority to invite the Principal

Inspector for the region to participate in any multi agency drinking water quality andhealth forums.

For further information on the Water Supply (Water Quality) Regulations 2001, or the

microbiological and chemical parameters covered by the regulations please refer to

the DWI website, http://www.dwi.gov.uk

If you have a need for more specific information than that on our website, please

contact us on the DWI enquiry line: 020 7082 8024.


43/70

Drinking water 2005

38


44/70


39

Annex 1Other sources of information

There are two additional sources of information published this year, a CD andcontent published to the DWI website at http://www.dwi.gov.uk

Content of the CDThe CD is supplied with this document in a folder.

Part 1 Drinking water standards and science

Part 1 covers:

How is drinking water quality regulated?

The drinking water standards European and National

Drinking water science

Drinking water research completed in 2005 and ongoing.

Part 2 Drinking water safety

This part presents:

Chief Inspectors statement

An overview of water safety plans

A review of the performance of the industry in 2005 Individual summary tables of company performance.

Part 3 Regional reports

There are six regional reports for England and one for Wales (In English and Welsh).

The reports cover:

Eastern region

Midlands region

Northern region

Southern region

Thames region

Western region

Wales.


45/70

Drinking water 2005

40

They summarise data from 2005 for the region under the following headings:

Water sources

Drinking water quality testing

Drinking water quality results Consumer perceptions of drinking water

Incidents in 2005

Technical audit activity in the region

Local authority consultation

Consultation with health professionals.

Supplementary informationIn addition, published to the CD and DWI website are the following items.

Water company look-up tables

These summarise, by parameter, the results of water company tests taken in 2005.

They provide information on:

what was tested

how many tests were performed

the range of results of the tests

how many failures were detected.

Incidents in England and Wales 2005

In order to assist the sharing of learning, the Inspectorate has published a compiled

list of incidents that occurred in 2005 which illustrates the nature and cause of each

incident and the main actions and findings of the Inspectorate. Regional extracts of

this overall list are contained in each regional report (Annex 3).

Inspectorates website

The inspectorate has a website at http://www.dwi.gov.uk and in addition to the

content described above, the following information can be found:

The performance of the Inspectorate against its targets

The prosecution record for the Inspectorate

The details of where the Inspectorate has provided advice or made presentations.


46/70


41

Annex 2Glossary and description of standards

These definitions will assist the understanding of the Report where technical terms

have been used.

Aggressive a term used to indicate that the water has a

tendency to dissolve copper (and other metals)

from the inner surface of a pipe or water fitting

such as a tap.

Aesthetic associated with the senses of taste, smell and sight.

Alkali a solution containing an excess of free hydroxyl

ions, with a pH greater than seven.

AQC Analytical Quality Control is the method used to

ensure that laboratory analysis methods are

performing correctly.

Aquifer water-containing underground strata.

Atrazine a chlorotriazine herbicide registered for use in

forestry and in sweetcorn.

Authorised Departure authorisation for a water company to temporarily

supply water exceeding a drinking water standard,

granted by the Authorities only when there is no

risk to human health.

Bulk supply water supplied in bulk, usually in treated form, from

one water company to another.

Chloramine a substance formed by reaction between chlorine

and ammonia, used as a disinfectant in distribution

systems because of its long lasting properties

compared to chlorine.

Chloramination The process of generating a chloramine disinfectant

residual in water leaving a treatment works.

Chlorine residual the small amount of chlorine or chloramines

present in drinking water to maintain its quality as it

pa

part 3 - wales (in english)

Documents