Tansa Lake Overflows After Heavy Monsoon Rains, Dam Gates Opened as Mumbai's Water Reserves Strengthen

In an official update, the civic body stated that Tansa Lake, which has a maximum storage capacity of 14,508 crore litres, is among the seven reservoirs that provide drinking water to Mumbai. The reservoir started overflowing following sustained heavy rainfall across the region during the ongoing monsoon season. The BMC also shared visuals showing water gushing from the dam and tagged Maharashtra Chief Minister Devendra Fadnavis and other senior officials in its announcement.

The overflow at Tansa Lake comes two weeks after Vihar Lake and Tulsi Lake, the two reservoirs located within Mumbai's municipal limits, began overflowing on July 8. Their early overflow occurred considerably ahead of previous years despite the combined water stock across the seven reservoirs standing at only 41.43 percent at the time. The BMC had attributed the improvement in water reserves to an intense spell of rainfall that followed a slow start to the monsoon.

⛈️ संपूर्ण बृहन्मुंबई क्षेत्राला पाणीपुरवठा करणाऱ्या तलावांपैकी महत्त्वाचा असणारा तानसा तलाव आज सकाळी ८.५१ वाजेच्या सुमारास ओसंडून वाहू लागला आहे. तानसा धरणाचे दरवाजे उघडले आहेत.

तानसा तलावाची कमाल जलधारण क्षमता १४,५०८ कोटी लीटर इतकी आहे.

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⛈️ Tansa Lake, one of the lake… pic.twitter.com/Hooh1vgfva

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— माझी Mumbai, आपली BMC (@mybmc) July 22, 2026

Mumbai receives its drinking water from seven reservoirs: Upper Vaitarna, Modak Sagar, Tansa, Middle Vaitarna, Bhatsa, Vihar, and Tulsi. These reservoirs are spread across Mumbai, Thane, and Palghar districts and collectively form the city's primary water supply network.

With Tansa Lake now joining Vihar and Tulsi among the overflowing reservoirs, the overall water storage position is expected to improve further. However, the BMC did not immediately release updated combined water stock figures following Wednesday's development.

The civic body has continued issuing regular rainfall and reservoir status updates throughout the monsoon season as persistent heavy rainfall has caused intermittent disruption to road and rail traffic across Mumbai in recent weeks. The overflow of Tansa Lake marks another significant milestone in the city's monsoon water management, strengthening drinking water reserves for the Mumbai Metropolitan Region while highlighting the impact of sustained seasonal rainfall on the reservoir network.