With Cantareira in a critical situation, Sabesp activates an additional capture at Serra do Mar

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The new structure allows up to 2,500 liters of water per second to be transported from the Itapanhaú River basin, in the Serra do Mar, to the Alto Tietê system, which today plays a fundamental role in supplying Greater São Paulo.

The completion of the works comes at a critical time, when the Cantareira system, the main reservoir in the region, is currently operating in the restriction zone (level 4), with a useful volume of less than 20%. The Jaguari-Jacareí Dam, one of the main dams in this system, recorded this Tuesday 16.8% of its capacity, the worst mark since the water crisis of 2014. With a level below 30%, it was already necessary to pump water from the Paraíba do Sul river basin.

According to César Soares, meteorologist at Climatempo, the year 2025 was harsh for watersheds, with above-average precipitation recorded only in April. However, projections indicate a change in the climate pattern.

— The scenario for the next few months is very favorable for precipitation in the hydrographic basins, according to Climatempo forecasts, the trend is for above-average precipitation, including at the beginning of 2026, good news to alleviate the drought that is hitting the main source of supply for Greater São Paulo — says Soares.

Despite this optimism, the expert warns that it will be necessary to maintain monitoring throughout next year, including during the dry season, to confirm whether there will be a full recovery of storage levels.

For now, the determination of the regulatory bodies (ANA and SP Águas) keeps Cantareira in the restriction zone throughout December, thus reinforcing the importance of the new Itapanhaú pipeline to balance the water supply of the metropolis.

The transfer operation begins in the Sertãozinho River, one of the tributaries of the Itapanhaú, located about 60 kilometers from the capital São Paulo. The project, which benefited from an investment of 300 million reais, required complex engineering solutions to minimize interventions in the Serra do Mar National Park.

A route of approximately 9 kilometers begins, made up of pipes supported on concrete blocks and a 500-meter tunnel dug into the mountain, near the Mogi-Bertioga highway, avoiding the burying of the pipes and preserving native vegetation. The system performs an initial pumping to overcome a level difference of 98 meters and, from this point, gravity guides the flow to its destination.

The subsidy granted by SP Águas authorizes the maximum transfer of 2,500 liters per second, or an increase equivalent to 17% of “new water” to the reservoir. From there, the Integrated Metropolitan System distributes the resource to the entire region, which has nearly 22 million inhabitants.

— We operate in regions with low natural water availability, highly urbanized and densely populated. This is another project aimed at guaranteeing more water to the population, looking for sources that were not previously used for supply — said Roberval Tavares, Executive Director of Engineering and Innovation of Sabesp.