By Brazil Stock Guide – Sabesp (B3: SBSP3), privatized in July 2024 and now controlled by Equatorial Energia, reported a further drop in water storage across the São Paulo Metropolitan Region. On Sept. 21, 2025, reserves slipped to 32.1% (624.22 hm³) from 32.3% the day before. The 0.2-point decline deepens the shortage to the lowest level for this date in a decade.
The Cantareira system, the region’s main source, fell to 29.5% (289.95 hm³) from 29.7%. Alto Tietê decreased to 25.5% (143.11 hm³), while Guarapiranga dropped to 47.3%. Cotia and São Lourenço showed sharper falls, to 50.8% and 44.8%, respectively. Rio Grande eased to 53%, while Rio Claro held steady at 19%.
No rainfall was recorded on Sept. 21. For the month, Cantareira accumulated only 0.2 mm, compared with a historical average of 79.5 mm. “Current levels reinforce the urgency of control measures to secure supply until the rainy season,” said Arsesp, the state sanitation regulator.
Storage has deteriorated sharply from 2024, when reservoirs stood at 53.2% (522.63 hm³) on Sept. 20 — a 21-point difference in one year. The contrast with 2015, when levels sank near 20% during the worst drought in decades, underscores rising risks.
In response, Sabesp has cut network pressure overnight since August. On Friday, Arsesp extended the restriction to 10 hours, from 7 p.m. to 5 a.m., and ordered daytime adjustments to balance supply.
Falling reserves threaten water for 22 million residents of Brazil’s largest city region, reviving memories of the 2014–2015 water crisis. With summer rains still months away, tougher rationing measures cannot be ruled out.
Over the past decade, Sabesp inaugurated the São Lourenço system and built reservoir interconnections to strengthen water security in Greater São Paulo. Falling reserves threaten water supply for 22 million people in Brazil’s largest metropolitan region and revive memories of the 2014–2015 crisis. With summer rains still months away, the risk of tougher restrictions is growing.
Equatorial Group, traditionally an electricity distributor, took control of Sabesp in 2024 as part of its expansion into Brazil’s sanitation sector.
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