Mumbai: Lake levels at 32.85 per cent, evaporation threat real

The Tansa, a large lake in Thane district. File pic

The summer heat is putting pressure on the city's drinking water supply. Lake water evaporation has risen compared to the past two years. While the increase is minor, a former BMC official said it could become a serious issue by May. In the past six days, lake levels have dropped by 2.21 per cent. During the same period last year, the drop was 2.19 per cent, and in 2023, it was 2.1 per cent. Compared to 2023, the current water stock has gone down by 0.11 per cent, and it's 0.02 per cent lower than in 2024.

Officials from the civic hydraulic department said, "The chances of lake water evaporating are higher this year compared to last year, due to the intense sun." However, they added that the difference is still "very minor." Hydraulic Engineer Purushotam Malwade said, "Considering all aspects, we have already requested the state government to release water from its reserved stock. We have planned to ensure water supply till the end of July."

The Bhatsa is a major source of drinking water for the city. File Pic/Sayyed Sameer Abedi

The BMC has asked for 68,000 million litres of water from Upper Vaitarna and 1.13 lakh million litres from the Bhatsa dam. Both dams are owned by the state government. Apart from these, the BMC also receives water from civic-owned lakes such as Middle Vaitarna, Modak Sagar, Tansa, Tulsi, and Vihar.

As of Tuesday, the city's total water stock stands at 4,75,494 million litres - 32.85 per cent of the full lake capacity. On the same date in 2024, the stock was 3,96,327 million litres (27.38 per cent), and in 2023, it was 4,86,563 million litres (33.62 per cent). The total storage capacity of all the lakes is 14,47,363 million litres.

Looking at earlier data, on April 2, 2025, the water stock was 5,07,445 million litres (35.06 per cent). On April 2, 2024, it was 4,27,981 million litres (29.57 per cent), and on April 2, 2023, it was 5,16,945 million litres (35.72 per cent).

Tanker strike fears

Meanwhile, the Mumbai Water Tanker Association has announced a strike in protest of the Central Ground Water Authority's licensing decision. Around 1800 tankers supply non-potable water across the city. This water is mainly used for commercial purposes and infrastructure projects.

Ankur Sharma, spokesperson of the Mumbai Water Tanker Association, said, "The strike could create a shortage of 150 to 200 million litres of non-potable water. These tankers supply water to commercial buildings and construction sites. They also support ongoing infrastructure projects like road concreting and the sea link. If the supply stops, it will impact both private and government construction work."

Concerns raised

Madhu Vannier, who lives in Evershine Cosmic, Veera Desai Road Extension, Andheri West, said, "We always face water shortage because our building is at the far end of the water supply network. During summer, things get worse. If evaporation is already higher than last year, I can't even imagine what May will be like for our society." Shiv Sena (UBT) leader Aditya Thackeray also raised concern in a letter to the civic chief, urging the BMC to declare the current status of the city's water supply.

Civic activist Anil Galgali said, "There have been strict rules about rainwater harvesting since 2009, but who follows them? If this rule is enforced strictly, it will save potable water. Rainwater can be used for non-potable purposes. We can't stop lake water from evaporating, but we can reduce potable water use by switching to alternatives," he said.

Milind Mhaske, founder of Praja Foundation, said, "We can't stop evaporation, but the BMC should work to prevent water wastage from leakages. Due to Mumbai's geography and good water distribution planning, the harsh effects of summer aren't strongly felt. But we must plan for the future and assess our water needs today."

4,75,494 ML
Total water stock as of Tuesday, April 8