São Paulo's regulator raised SABESP's customer tariffs by 6.1106% from January 1, 2026, the first adjustment under Concession Contract 01/2024. Its own equilibrium calculation for the same contract year had shown a variation of 6.81%.
Two tariffs, almost identical
In November 2025 the São Paulo State Public Services Regulatory Agency (ARSESP) calculated an equilibrium average tariff of R$6.7673 per cubic meter for contract year 2, fixed at October 2025 prices by Deliberation 1,748. The contract tariff in Annex IV, once updated, came to R$6.7655 per cubic meter. ARSESP concluded that the application tariff should be the contract tariff with monetary correction, and customer tariffs rose by the IPCA inflation correction for June 2024 to October 2025.
What sits behind the number
The equilibrium calculation used required revenue of R$25,348.70 million against base tariff revenue of R$24,942.97 million, on a metered volume of 3,677 million cubic meters. The gross regulatory asset base, excluding land, stood at R$132,140.45 million at the end of 2023 in June 2024 prices, up from R$127,450.10 million a year earlier.
The asset base predates the spending surge
Those asset values come from before the heaviest investment years. SABESP recorded R$15.2 billion of capital expenditure in 2025 and guided about R$20 billion for 2026, within a plan of around R$70 billion for 2024–2029. Periodic tariff reviews now come every five years instead of four, and the next is scheduled for November 2029, the year of the concession's universalization deadline.
The report also answers how ARSESP and SP Águas divide service and water decisions, where the Cantareira stood after the 2025–2026 drought, and which informal and rural targets remain furthest from completion. The full report, Water Systems Overview: SABESP, is available for USD 499 at https://ourfuturewaterintelligence.com/reports/water-systems-overview-sabesp. For a free overview, read the SABESP Utility Snapshot at https://ourfuturewaterintelligence.com/utilities/sabesp.