Mumbai’s Lifeline Lakes Brimming: Water Stock Crosses 96%, Assures 362 Days of Supply

Mumbai’s relentless monsoon showers over the last few weeks have transformed the city’s water story from anxious anticipation to confident assurance. The seven reservoirs that quench the thirst of India’s financial capital are now filled to 96.16% of their live storage capacity—a remarkable improvement from 95.36% recorded at this time last year.

According to data released by the Brihanmumbai Municipal Corporation (BMC), the combined live storage as of 6 am on 26 August 2025 stands at 1,391,854 million litres, against the city’s annual requirement of 1,447,363 million litres. With daily supply pegged at 3,850 million litres (short of the city’s actual demand of 4,200 million litres), Mumbai currently has a comfortable cushion of 362 days of water supply in store.

Lake-Wise Update

The reservoirs spread across Mumbai and its adjoining regions have all recorded robust inflows thanks to heavy rainfall in their catchment areas. Here’s how they stand today:

• Bhatsa (48% share): At 94.18% capacity, holding 675,335 million litres. Recorded 85 mm rainfall in 24 hours, seasonal tally at 2,424 mm. Nearly 70% of this water is reserved for Mumbai, making Bhatsa the city’s most critical reservoir.
• Upper Vaitarna (16% share): At 95.97% capacity, with 217,886 million litres. Daily rainfall 59 mm, seasonal tally 1,796 mm.
• Middle Vaitarna (12% share): At 98.22% capacity, holding 190,077 million litres. Rainfall 89 mm, seasonal tally 2,928 mm.
• Modak Sagar (11% share): Touching the brim at 100% capacity, holding 128,925 million litres. Seasonal rainfall 2,845 mm. Overflow was recorded at 6:27 am on 9 July 2025, notably earlier than last year’s July 25 overflow.
• Tansa (10% share): At 99.18% capacity, storing 143,887 million litres. Rainfall 48 mm, seasonal tally 2,606 mm. Overflow occurred on 23 July 2025.
• Tulsi (2% share): At 100% capacity with 8,046 million litres. Seasonal rainfall a staggering 3,462 mm. Overflow this year recorded on 16 August.
• Vihar (1% share): At 100% capacity, with 27,698 million litres. Seasonal rainfall 2,167 mm.

Additionally, the Barvi dam, which supplies neighbouring regions like Thane, Kalyan-Dombivli, Ulhasnagar, Mira-Bhayander, Bhiwandi, and Navi Mumbai, stands at 98.63% capacity with 334,190 million litres—an encouraging figure for MMR at large.

Distribution & Supply Dynamics

Mumbai’s water supply system works like a finely tuned orchestra:

• Western suburbs (Dahisar to Bandra, and Mahim to Malabar Hill) receive water from Modak Sagar, Tansa, and the Vaitarna trio (Upper, Middle, Lower).
• Eastern suburbs (Mulund to Sion, extending to Mazgaon) rely on the Bhatsa system, which also includes Tulsi and Vihar. This water is treated at the Panjarpur Water Treatment Plant before distribution.

With most reservoirs either full or near capacity, the BMC has ruled out immediate water cuts—a major relief for households and businesses alike.

Weather Outlook

While the reservoirs are flush, the city continues to experience monsoon activity. The Santacruz observatory reported 30.4°C maximum and 26.3°C minimum temperatures on Sunday, while Colaba saw a high of 29.7°C and a low of 25.8°C. Rainfall in the 24 hours ending 8 am on 23 August was modest—1.90 mm in the city, 4.52 mm in eastern suburbs, and 1.94 mm in the western suburbs.

Tidal activity, however, keeps the civic authorities on alert. A high tide of 4.53 metres was expected at 12:48 pm on 26 August, while a low tide of 0.96 metres at 6:52 pm. The BMC has urged residents in low-lying areas to remain cautious, particularly during high-tide windows when rainwater drainage slows down.

Expert Take

With 362 days of assured supply and robust lake levels, Mumbai is better placed this year to navigate its water needs compared to the previous monsoon cycle. However, the city’s precarious balance between rainfall, demand, and infrastructure efficiency underscores the need for long-term strategies—especially given its expanding population and climate uncertainties.

For now, Mumbaikars can breathe a sigh of relief: their lifeline lakes are brimming, promising a year of water security.

Data Attribution: numerical.co.in