Mumbai’s water cut and supply gap persist as demand heads for a 57% rise by 2041

Mumbai is already short of more than 500 million litres of water a day (MLD), and the gap could widen to 2,324 MLD by 2041 as the big projects meant to plug it remain years from reaching taps. The city is under a 10% water cut, monsoons are turning unpredictable, and demand is projected to jump 57% in the next 15 years.

According to a TOI report by Biju Mathew, the Brihanmumbai Municipal Corporation (BMC) draws about 4,100 MLD from seven lakes and dams. The city's actual daily requirement is estimated at 4,600 MLD to 4,665 MLD.

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The BMC's environment status report 2025-26 expects demand to touch 6,424 MLD by 2041, which is 56.7% above what the city gets today. That leaves a gap of 2,324 MLD, even before the challenge of finding new sources and delivering the water efficiently.

Monsoon shortfall adds to the strain

This year's monsoon has added to the pressure. Mumbai's reservoirs did not fill to full capacity after deficient rain in August and September. In June, water levels in the seven lakes had fallen below 10% of total capacity, and the BMC imposed stringent restrictions. Stocks recovered to around 96% by September, but the civic body still went ahead with the 10% cut, TOI reported.

The Maharashtra government has also ordered a minimum 10% cut in water supply in urban and rural areas from October 16, citing drought-like conditions.

Three projects hold the key

The BMC has identified six more sources that are expected to add 3,303 MLD. Three of them, Gargai, Pinjal and the Damanganga-Pinjal inter-state scheme, account for 2,891 MLD, or about 88% of the proposed addition. The other three sources together make up the remaining 412 MLD.

Gargai, expected to supply 440 MLD, is under construction and due for completion by 2029. Pinjal, which is to contribute 865 MLD, is still at the planning stage. The 1,586 MLD Damanganga-Pinjal scheme is yet to move beyond paper.

Earlier, the BMC had planned dams on the Gargai, Pinjal and Damanganga rivers on the recommendation of the Chitale committee in 1996, according to a PTI report. The same report said the civic body was then still awaiting forest and wildlife clearances for the Rs 3,105 crore Gargai dam, which is to be connected to the nearby Modak Sagar lake through a tunnel.

The Damanganga-Pinjal link is the most complex of the three. According to the National Water Development Agency (NWDA), the project envisages diverting surplus water of the Damanganga river through reservoirs at Bhugad and Khargihill to the Pinjal reservoir in the Vaitarna basin, from where it would be carried to Mumbai.

NWDA project documents say the link and the Pinjal project together would provide 2,451 MLD and generate 5 MW of hydropower. The cost was estimated at Rs 3,008 crore at 2015-16 prices. NWDA completed the detailed project report in March 2014, more than a decade ago.

Because the scheme spans Gujarat and Maharashtra, it needs coordination between the Centre and both state governments. The delays matter because Mumbai cannot depend on its seven existing reservoirs alone to bridge the widening gap.

Desalination is no quick fix

Desalination is the other option on the table. IDE Technologies says it has been awarded the engineering, procurement and construction contract by the BMC for a seawater reverse osmosis plant at Manori on the western coast. It will be built with Indian firm GVPR Engineers Limited.

The first phase will produce 200 MLD. The intake, outfall, tunnels, pumping station and storage are being built for an ultimate capacity of 400 MLD. IDE will operate and maintain the plant for 20 years after commissioning.

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The numbers show the limits of the option. The first phase would cover about 4% of Mumbai's current daily requirement of 4,600 MLD. Even the full 400 MLD would be under 9%.

Execution is the real test

The issue came to the fore during a visit by Mayor Ritu Tawde, standing committee chairman Prabhakar Shinde and other ruling BJP leaders to the Tansa and Modak Sagar lakes, TOI reported. They pressed hydraulic engineering officials for details on how to speed up the Pinjal and Damanganga-Pinjal projects.

The challenge now is not announcing new sources but getting clearances, coordinating across governments and finishing projects on time. With a deficit of over 500 MLD already on the ground, the 2041 projection describes a gap that has begun to open today.

(With inputs from PTI)