The Company is engaged in the operation of the public water supply and sewage treatment systems for the population of 368 of the 645 municipalities in the State of São Paulo. In addition, it is also responsible for the sale of treated water and provision of treated sewage services to 6 municipalities of the São Paulo Metropolitan Region that are not under its direct operation.

In the operated municipalities, water distribution network is approximately 58,000 kilometers long. The length of the sewage, trunk sewer, interceptors and outfalls network is of approximately 37,100 kilometers.

In 2005, SABESP brought treated water to 158,000 new homes and added another 142,000 homes to its sewage collection network. Therefore, it served 100% of the urban homes with water, 78% with sewage collection networks and treated over 60% of the collected sewage.