The Cantareira System entered Alert Band 3 on Wednesday, July 1, 2024, after water levels fell below 40 percent of total capacity [1, 3, 5].
This shift is critical because the system serves as the primary water source for the Sao Paulo metropolitan region. The move to an alert status triggers mandatory reductions in the amount of water that can be extracted from the reservoirs to prevent a total collapse of the supply.
Following the closure of June, the useful volume of the reservoir system fell to between 39.87 percent [1] and 39.9 percent [2] of its total capacity. This decline represents the worst end to a first semester since 2022 [2].
Because of this drop, Sabesp, the state-owned water company, was required to reduce its water extraction limit. The previous normal limit of 33 cubic meters per second [3] was lowered to 27 cubic meters per second [3].
These operational limits are established by the National Water Agency (ANA) and Arsesp, the regulatory agency for public services in Sao Paulo. The restrictions apply to the wider metropolitan area, including municipalities such as Santo Andre, and Sao Caetano do Sul [1, 2].
The reduction in extraction is a preventive measure designed to preserve the remaining water levels during the drier months. Officials said they monitor these bands to determine when more drastic conservation measures or rationing may become necessary to ensure the city's water security [1, 3].
“The Cantareira System entered Alert Band 3 on Wednesday, July 1, 2024”
The transition to Alert Band 3 indicates a significant vulnerability in Sao Paulo's water infrastructure. By reducing the extraction limit, authorities are attempting to extend the lifespan of current reserves, but the fact that this is the lowest first-semester level since 2022 suggests a recurring struggle with climate volatility and water management in the region.
