Australian Capital Territory Rainwater tanks - Canberra Capital Territory Rainwater tanks ... for above or below ground tanks. ... is a rainwater tank on a stand with a simple tap outlet for filling

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  • Australian Capital Territory

    Rainwater tanks

    Guidelines for residential properties in Canberra

    Reprinted June 2006

  • Contents

    Foreword 3

    Commonly asked questions

    Whyinstallarainwatertank? 3

    HowcanIuserainwater? 4

    HowbigatankdoIneed? 4

    CanIdisconnectfromtheACTEWwatermains? 4

    Whattypeofrainwatertankisbestforme? 5

    Howmuchwillitcost? 5

    Arethereanyfinancialincentives? 5

    WillIpaylessonmywateraccount? 6

    WhatworkcanIdowithoutaplumbingorelectricitylicence? 6

    Arethereapprovalcosts? 6

    Istankwatersafetodrink? 6

    ShouldIaddfluoride? 7

    ShouldIusekerosenetocontrolmosquitoes? 7

    DoIneedtofiltertankwater? 7

    Rainwater assembly options

    Illustrations 8-0

    Installation requirements

    Rainwatertankbases

    Coversandlids

    Screensandstrainers

    Firstflushrainwaterdiverter 2

    Plumbingpipesandfittings 2

    Lightproofing 2

    Pumps 2

  • 2

    Top-upfacility 3

    Overflow 3

    Maintenance and system management

    Drinking water safety

    Healthconsiderations 4

    Disinfection 5

    Roofmaterials 5

    Leadflashing 5

    Paintsandcoatings 5

    Regulations

    Planningandbuildingapprovals 6

    Buildingwithineasementsornearutilityassets 7

    Plumbingapprovals 7

    Plumbingrequirements 7

    Rainwaterplumbingmaterialsandlabelling 8

    Proximitytootherservices 9

    Backflowprevention 9-20

    Contact details 21

    References 21

    Appendix A 22

  • 3

    Foreword

    TheACTGovernmentiscommittedtothewiseuseoftheregionswater.Thestrategyforsustainablewaterresourcemanagement,'Think water, act water',providesaclearvisionandarangeofinitiativesforthesustainableuseofwaterresources.ItsetstargetstoreduceCanberra'spercapitamainswaterconsumptionby2percentby203and25percentby2023.OneproposalistopromotetheuseofrainwatertankstohelpreducethepercapitademandontheACTEWwaternetwork.

    ThisRainwaterTankGuidehasbeenpreparedinpartnershipbetweenActewAGL,EnvironmentACT,theACTPlanningandLandAuthorityandACTHealthandprovidesguidanceontheinstallationofrainwatertanksinresidentialproperties.

    Commonly asked questions

    Why install a rainwater tank?

    Rainwatertankscanmakeanimportantcontributiontowardsreducingthedemandourhomesmakeondamstorages.Rainwatertankscanalsohelpslowtheflowofstormwaterfromoururbanenvironmentintolocalcreeksandrivers.Byusingrainwateryoucanalsomakesavingsonyourwateraccount.

    Theseguidelineshavebeenpreparedtohelpyouunderstandthekeyissuesthatneedtobestudiedwhenplanningasuccessfultankinstallation.Subjectscoveredinclude:

    howmuchwatertostore, healthandsafety, regulationsand installationrequirements.

    AlltheessentialrequirementsofActewAGL,ACTHealth,theACTPlanningandLandAuthorityandEnvironmentACThavebeenincludedtomakeyourinvestigationseasier.

    However,whilethisinformationwascorrectatthetimeofprinting,requirementscanchange.Youareadviseditisyourresponsibilitytoensureyouareawareofuptodatelegislationandregulations.Youshouldcontactrelevantagencieslistedonpage2toensureyouhavethelatestinformation.

  • 4

    How can I use rainwater?

    Ataponasimplerainwatertankcan:

    supplyirrigationdrippersorasoakerhose, fillabuckettowashacar, top-upaswimmingpooland fillanornamentalpond.

    Withadditionalplumbingarainwatertankcansupplywaterto:

    ahose, irrigationspraysand aflushingtoilet.

    Withcarefulcontrolofwaterqualityarainwatertankcanalsobeusedto:

    fillawashingmachine, runshowersandbathsand providesafedrinkingwater.

    How big a tank do I need?

    Estimatingthesizeofatankrequiresacombinationofexperienceandcalculation.Rainfallisvariableanddemandwillchangewiththeseasonsandtheneedsoftheresident.Inaddition,thesizeoftherainwatertankwilldependon:

    howmuchrainfallseachyear, theareaofroofavailabletocapturetherain, howyouplantousetherainwater, thenumberofpeoplelivinginyourhouse, thecurrentwaterusagerateand availablespacetoinstallthetank.

    Youcanestimateyouryearlywatersavingswiththecalculatoratwww.thinkwater.act.gov.au/calculators/water_calculators.shtmloratAppendixAofthisbook.Theexperienceofyourlocalrainwatertanksupplierwillalsobeinvaluable.

    Can I disconnect from the ACTEW water mains?

    Makingyourhomeself-sufficientandindependentfromtheACTEWnetworksupplyrequiresalargecontributingroofareaandsubstantialtankcapacity(probablygreaterthan00,000litresforanaveragehouse).Canberrahasavariablerainfallandissubjecttodrought,sorigorouswatersavinghabitsarerequiredifyouwantyourhouseholdtobeself-sufficient.Eventhenthereisnoguaranteethatyouwouldneverrunoutofwater.

  • 5

    ActewAGLcandisconnectyourmainspressurewatersupplyinaccordancewiththestandardscheduleofprices.Afterdisconnectionyouwillnotbebilledforwaterusagechargesbutyouwillhavetopayanetworkavailabilitycharge,sothereisnofinancialbenefitindisconnecting.Keepingthenetworksupplyforemergenciesortop-upisausefulsafeguard.

    What type of rainwater tank is best for me?

    Mostresidentialrainwatertanksaremadefromplastic,fibreglass,concrete,corrugatedgalvanisedsteelorcorrugatedsteellinedwithplastic.

    Almostanytankmaterialcanbeusedtostorewaterforirrigationortoiletflushing.

    Tanksusedfordrinking,foodpreparation,washingclothes,showersorbathingshouldbemadefrom,orlinedwith,adrink-safe(foodgrade)material.

    Yourtankmanufacturercanadviseaboutthebestmaterialandmosteconomicalsolutionforaboveorbelowgroundtanks.

    How much will it cost?

    Rainwatertankpricesvaryaccordingtosize,material,finish,strengthandquality.Itisworthcomparingpricesfromseveralsuppliers.

    Otherinstallationcostswillvaryaccordingtothecomplexityofyoursystembutmayinclude:

    transportation, alterationtoguttersanddownpipes, tankstandfoundationwork, afirstflushrainwaterdiverter, inletandoverflowpipeinsectscreens, plumbingpipesandfittings, engagingalicensedplumberforhouseholdplumbing, watertop-upfacility, apumptoincreasepressure,andflowratesand associatedelectricalworks.

    Are there any financial incentives?

    Financialincentivesintheformofrebatesmaybeavailabletoassistyourpurchaseofarainwatertank.ThedetailsofanycurrentrebateprogramsareavailablefromtheThinkwaterwebsite:www.thinkwater.act.gov.au

  • 6

    Will I pay less on my water account?

    YoucanexpecttomakesomesavingsonyourActewAGLwateraccountifyouusearainwatertank.However,youmaywishtoestimatewhatthesesavingsarelikelytobebeforeinstallingarainwatersystem.

    What work can I do without a plumbing or electricity licence?

    Taking due care, a handy person can install:

    tanksandstands, irrigationsystemsfromadedicatedtank, apressureboostingpumpusedsolelyforirrigationand rainwaterguttering,downpipesandstormwaterdrains. A licensed plumber must be engaged to install:

    rainwaterplumbingpipesprovidingwatertothehouse, pressureboostingpumpsforhouseholdrainwaterplumbingand tanktop-upsystems(fedfromthecitywatersupply).

    ForfurtherdetailseethesectiononRegulations.

    A licensed electrician must be engaged to modify or install:

    poweroutletsand fixedwiringtopumpsorelectricalappliances.

    ForfurtherdetailseethesectiononRegulations.

    Are there approval costs?

    Youmaybesubjecttogovernmentchargesforplanning,buildingandplumbingapprovals.Governmentplumbingchargesmaybeincludedinyourplumbersaccount.DetailsareavailableinthefeesandchargesbookletavailableattheACTPlanningandLandAuthorityCustomerServiceCentre.

    Is tankwater safe to drink?

    TheuseoftankwaterfordrinkingorfoodpreparationisnotrecommendedwherethereisapotablenetworksupplyavailablewhichmeetstheAustralianDrinkingWaterGuidelines.Ifyouchoosetoinstallarainwatertanktoprovidedrinkingwater,youshouldcontactACTHealthforadviceandfollowthesuggestionsincludedinthesectionon'drinkingwatersafety'.

  • 7

    Should I add fluoride?

    Rainwaterdoesnotcontainfluoride.Youshouldnotaddfluoridedirectlytotherainwatertank,asitisverydifficulttocontrolthecorrectdosagerate.Talktoyourdentistaboutsubstitutes.

    Should I use kerosene to control mosquitoes?

    Lowoxygenlevelsintankwater,causedbyexcessivesludge,willattractmosquitoes.Youmayhaveheardthatateaspoonofkerosenepouredontothesurfaceoftank-waterwillstopmosquitoesfrombreeding.Thisistrue,howeverthereisnoneedtousekeroseneasfineinsectscreensorfinemeshscreensproperlyinstalledoninletandoverflowpointswillpreventmosquitoesenteringthetank.Undernocircumstancesshouldkerosenebeusedifthetankisfordrinkingwater.KerosenemayalsobedamagingtoplasticorAquaplatecoatings.

    Do I need to filter tankwater?

    Sedimentandorganicmaterialaccumulatesinrainwatertanks.Afilterontheirrigationsystemcanhelppreventsprinklerheadsfrombecomingcloggedwithsludge.

    Afiltermaybeinstalledatthekitchensinktoremoveimpuritiesfromdrinkingwater,howevertheunitshouldbemaintainedinaccordancewiththemanufacturersinstructionstopreventthefilterbecomingasourceofcontamination.

  • 8

    Rainwater assembly options

    Thefollowingassemblyoptionsillustratesomebasicrainwatertankandplumbingconfigurations.

    Basic tank

    Thesimplestinstallationisarainwatertankonastandwithasimpletapoutletforfillingajugorbucket.

    Tap with basic irrigation system

    Adedicatedabove-groundtankcanrunasoakerhoseoradrippersystem(bygravity)forthegardenorvegetablepatch.

  • 9

    Pump connected to irrigation system with sprinklers

    Apumpmaybenecessarytoprovidethepressurerequiredforirrigationsprinklersormicro-sprays.Therainwatertankmaybeaboveorbelowtheground.*

    Tank connected to toilets, washing machines and diswashers

    Toilets,washingmachinesordishwasherscanusetankwater.Apumpisusuallynecessarytoboostpressureandflow.Therainwatertankmaybeaboveorbelowtheground.*

    *Undergroundtankscanbeusedforirrigationsprinklersandhouseholdappliancesbutusuallywillneedapumpto

    boostpressureandflowrates.

  • 0

    Plumbingconsiderationsincludethefollowing.

    Washing machine options

    Washingmachinesusuallyhavehotandcoldwaterinlethoses.Thecoldwaterhosecanbeconnectedtoarainwateroutletormovedtothemains-waterifthetankrunsdry.Ifyouchoosetopermanentlyconnectthewashingmachinetoarainwateroutletitmaybenecessarytoinstallamainstop-upvalveatthetanktopreventthetankfromrunningdry.

    Dishwasher options

    Under-benchdishwashersareusuallyconnectedtothehotwatersupply.Ifthehotinlethoseisconnectedtoacoldrainwateroutlet,cycletimeswillbelonger.Ifadishwasherispermanentlyconnectedtotherainwateroutlet,youmayrequireamainstop-upvalveatthetanktomakesureitdoesnotrundry.

    Toilet cistern options

    Toiletcisternscanbeconnectedtoadedicatedrainwateroutlet,howeveryoumayneedamainstop-upvalveatthetanktomakesurethetankdoesnotrundry.Itisalsopossibletoconnectacisterntobothmains-waterandtankwateroutlets,providedthecisternhastwocisternvalves(withair-gapbackflowprevention).

    Toilet cistern assembly showing rainwater and mains-water connection

  • Installation requirements

    Herearesomeessentialsthatneedtobeaddressedwheninstallingarainwatertank:

    Rainwater tank bases

    Mostmetalorplastictanksmusthaveastandorbasetocarrythecombinedweightofthetankandwater.Mostflat-bottomedtanksarenotabletocarrytheheavyloadofwaterwithoutthesupportofastrong,levelandcontinuousbase.

    Whenarainwatertankisfull,everykilolitreofwaterweighs000kilograms(onetonne)soforsafetyitisimportanttoconstructatankstandthatisstrongandstable.Whenarainwatertankisemptyitcanbeblownoverbystrongwinds,somakesureyourtankisadequatelysecuredtothestand.Lightweightstandsshouldbesecurelyfixedtoaheavyfooting.

    Ifyouareintendingtouseapumptodistributethewater,therainwatertankcanbeatalmostanylevel.Ifyouwishtofeedthewaterbygravityitisusuallynecessarytoelevatetherainwatertankonasturdystand.

    Topreventexternalcorrosion,theundersideofmetalrainwatertanksshouldbekeptabovethegroundandsitonaself-drainingbase.

    Undergroundrainwatertanksmustbesealedagainsttheentryofsurfacerun-off,groundwaterandleakingsanitarydrainsthatmaycontainpesticides,fertiliserandanimal(orhuman)faecalmaterial.

    Undergroundtankswillfloatifsurroundedbywater.Makesuretheholeiswelldrained.Seekengineeringadviceifyouareuncertainaboutfoundationorgroundwaterconditions.

    Careshouldbetakennottoplacerainwatertanksinsidethedrip-lineofatreecanopy.Rootgrowthcandamagethebaseoftanks.Treesmayfailtothriveifraincannotgettotheroots.

    Covers and lids

    Arainwatertankshouldhaveanimperviouscovertopreventtheentryofdust,leaves,pollens,debris,vermin,mosquitoes,birds,animalsandinsects.

    Itisessentialtosealaccesshatcheswithstrong,close-fitting,childprooflids.

    Screens and strainers

    Theinlettotherainwatertankshouldincorporateameshscreenorstrainertopreventtheentryofliveinsectsandtocatchleavesandundesirableroofdeposits.Ameshwithopeningssmallerthanonemillimetreisveryeffectiveagainstmosquitoes.

    Thetankoverflowshouldalsobeprotectedwithaninsect-proofmesh.

  • 2

    First flush rainwater diverter

    Foraddedprotectionafirstflushrainwaterdivertercanbeinstalledtodivertthefirstflushofrain(containingroofdust,leaves,droppings,etc.)tothestormwaterandthendirectcleanwaterintotherainwatertank.

    Fabricated first flush Commercial first flush

    Firstflushdiversionvalvescanbefabricatedusingplumbingfittingsorpurchasedasacompletecommercialunit.

    Plumbing pipes and fittings

    Tankwatertendstobeacidicandcancorrodemetal.Itisadvisable,especiallyinnewinstallations,touserainwater-standardplasticpipesandfittings.SeethesectiononRainwaterplumbingmaterialsandlabelling.

    Light proofing

    Tanks,covers,plumbingpipesandfittingsshouldbelightprooftominimisedaylightpenetrationandalgalgrowthinthewater.

    Pumps

    Iftherainwatertankcannotbeelevatedsufficientlytogiveadequatepressuretoappliances,itmaybenecessarytoinstallapressure-boostingpump.Thefloatvalvesintoiletcisterns,irrigationsprinklersandthesolenoidvalvesinwashingmachines(ordishwashers)maynotoperateeffectivelywithoutadequatepressure.Thesizeofpumpwillvaryaccordingtotheheightofthetank,heightoftheappliance,diameterofplumbingpipesandtheflowrequirementsofappliances.Theservicesofahydraulicspecialistand/orpumpsuppliermayberequired.

  • 3

    Top-up facility

    Iftankwateristhesolesourceofsupplyforselectedtapsorappliances,youmayneedtotop-upthetankfromthedrinkingwaternetworkduringdryperiods.Top-upscanbedonewithahoseorapermanentoverheadfillingtapcomplyingwithACTPlanningandLandAuthorityplumbingregulations.Thetop-upfacilityforrainwatertanksshouldcomplywithAS/NZS3500Part.

    Whentopping-up,remember:

    hosesmustnotbeimmersedinthetankwater(seethesectiononbackflowprevention),

    onlytop-upalittle,perhaps0percent(leavingspacefortherainwhenitcomes)and

    duringwaterrestrictions,topping-upmaybebannedforsomeirrigationsystemsorrequireanexemptionforotheractivities.

    Overflow

    AlthoughitiscommonpracticeinCanberratoconnectroofdownpipesandtankoverflowstothehouseholdstormwaterdrainagesystem,thereisnoregulatoryrequirementtodoso.Itispermissibletospilltheoverflowontotheyard,howeveritisnotpermissibletoletanyofthatstormwaterrunoutsidetheboundariesofyourproperty.Itisalsoillegaltoconnectthetankoverflowtodischargeintotheseweragenetwork.

    Greatcareshouldbetakennottoletstormwaterpondunderfloorsorfloodaroundthefoundationsofbuildings.Highhumiditycanrottimberfloors,corrodemetalfittingsandpromotethecorrosionofreinforcementinconcreteslabs.Anincreaseinfoundationmoisturecontent,especiallyinclaysoils,cancausecrackinginhousewallsorevenoverturnretainingwalls.

  • 4

    Maintenance and system management

    Rainwatersystemsneedtobemaintainedregularlytoensurethatthewaterqualityisatitsbestforthepurposeyouintend.Tomaintainyourrainwatertankyoushouldensurethat:

    allthecomponentsarekeptingoodrepairandfreeofcorrosion,

    guttersarecleanedregularlytoremoveleaves,debrisandanimaldroppings(gutterguardscanhelpreducethebuild-upofleavesbutrequireregularchecking),

    rainwaterisnotpondinginroofgutters,

    therainwatertanksinletandoverflowscreensarecheckedandc...

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