The Cantareira water supply system entered an alert operational level on Wednesday, July 1, 2026 [2].
This shift forces the state water utility, Sabesp, to reduce the amount of water it captures from the reservoirs. Because the system serves the Greater São Paulo region, any restriction in water intake can impact millions of residents and businesses across one of the world's largest urban areas.
The transition to the alert phase follows a steady decline in water availability. By the end of June, the volume of water in the Cantareira system had fallen to 39.87% of its usable volume [1]. This drop below the 40% threshold triggered the more restrictive operating regime required to preserve the remaining supply.
Sabesp is now required to manage the reservoirs more conservatively to prevent a total depletion of the system. The alert level serves as a critical warning that the region's water security is precarious, a situation that often precedes more severe water rationing if rainfall does not increase.
While some reports have mentioned different timelines for restriction phases, the current operational status changed on Wednesday [2]. The utility is monitoring the levels daily to determine if further restrictions are necessary to maintain the city's basic water needs.
“The Cantareira system entered the 'alert' operational level, meaning Sabesp must reduce water capture.”
The move to an alert level indicates that Greater São Paulo is entering a period of heightened water vulnerability. By reducing capture rates now, Sabesp aims to avoid a complete collapse of the system, but this operational shift increases the risk of future water shortages if the dry season persists or if replenishment targets are not met.
