Economic-Financial Office and Investor Relations OfficeEconomic-Financial Office and Investor Relations Office

1Q11 Results1Q11 ResultsConference CallConference CallMay2011May2011

2

This presentation may contain forward-looking statements referring to SABESP’s business outlook. operating and financial results estimates. and growth prospects. These are only projections. and as such. they are exclusively based on SABESP’s management expectation in relation to the future of business and its continuous access to capital to finance the Company’s business plan. These forward-looking statements largely depend on changes in market conditions. governmental rules. industry performance and the Brazilian economy. amongst other factors. in addition to risks exhibited in disclosure documents filed by SABESP. Therefore. they are subject to changes without prior notice.

NoticeNotice

1Q10 1Q11

497.7 510.5

357.6 368.8Sewage

Water

Billed VolumeBilled Volume

3

Total billed water and sewage volume, including wholesale (million m³)Total billed water and sewage volume, including wholesale (million m³)

2.8%

3.1%

2.6%

855.3 879.3

732.0 731.3 742.6 746.0

755.3

1Q10 2Q10 3Q10 4Q10 1Q11

Produced Water Volume

497.7 493.7 493.6

508.0 510.5

1Q10 2Q10 3Q10 4Q10 1Q11

Billed Water Volume

25.7 25.8

26.0 26.0

26.2

1T10 2T10 3T10 4T10 1T11

Losses

Financial HighlightsFinancial Highlights

4

299.0

837.8

1,468.2

2,163.1

182.8

654.3

1,867.4

2,294.6

388.8

811.8

1,636.6

Net Income

EBITDA

Costs and Expenses

Net Operating Revenue

1Q11 (without effects) 1Q11 1Q10

6.1%

27.2%11.5%

21.9%3.1%

38.9%30,0%

Payroll and Benefits

Construction costs

Supplies Treatment supplies

Services Electric power

General Expenses

Depreciation and

Amortization

Credit write-offs

Tax expenses

357

442

34 36

215

130

73

143

10 27

557

439

3746

231

141127

228

3327

399

155

1Q10 1Q11 1Q11 (without effects)

59.5%

55.8%

8.1% 26.3%

7.4%

8.5% 75.2%

1.1%

5

Costs and Expenses Costs and Expenses (R$ million)(R$ million)

218.3%

% Net Revenue in 1Q1016.5% 20.4% 1.6% 1.7% 10.0% 6.0% 3.4% 6.6% 0.5% 1.3%

% Net Revenue in 1Q1124.3% 19.1% 1.6% 2.0% 10.1% 6.2% 5.6% 9.9% 1.4% 1.2%

(0.5%)

8.2%

11.7%

1Q10 - Net Income

Net Revenue Costs and Expenses

Other Revenues and Expenses

Net Financial Income Tax and Social

Contribution

1Q11 - Net Income

Net IncomeNet Income

6

299,0

131,5

(399,3)

(1,1)

168,8

(16,1) 182,8698,2

(24,3)

(179,8)

(157,6)

(37,5)

429,4

69,1

(195,9)

(85,5)

(34,3)

Main variations on Net IncomeMain variations on Net Income

1Q10 1Q11 Var.Net Income 1Q10 299.0

Net Operating Revenue 2,163.1 2,294.6 131.5

Costs and Expenses (1,468.2) (1,867.5) (399.3)

Other Revenues and Expenses 3.3 2.2 (1.1)

Net Financial (219.4) (50.6) 168.8

Income Tax and Social Contribution (179.8) (195.9) (16.1)

Net Income 1Q11 182.8

Exchange variationResult, net of financials Financial expenses, netIncome tax and social contribution Monetary variation

www.sabesp.com.br

IR Contacts

Mario Azevedo de Arruda Sampaio Angela Beatriz Airoldimaasampaio@sabesp.com.br abairoldi@sabesp.com.br(55 11) 3388-8664 (55 11) 3388-8793