07 July,2026 03:33 PM IST | Mumbai | Anushree Gaikwad
Located inside the Sanjay Gandhi National Park (SGNP), Vihar and Tulsi lakes are among Mumbai’s oldest water sources. Representational Pic
Mumbai's sprawling population depends on a vast and interconnected water network of seven major lakes and reservoirs that collectively supply around 3,850 million litres of water per day (MLD) to the city.
Managed by the Brihanmumbai Municipal Corporation (BMC), these water sources form the backbone of Mumbai's daily water supply. Interestingly, only two of the seven lakes, Vihar and Tulsi, are located within Mumbai's boundaries, while the remaining five are situated in the neighbouring districts of Thane, Palghar and Nashik regions.
Located inside the Sanjay Gandhi National Park (SGNP), Vihar and Tulsi lakes are among Mumbai's oldest water sources.
Vihar Lake, built in 1860 on the Mithi River, was Mumbai's first piped water source and continues to support parts of the suburban region. Tulsi Lake, constructed in 1879 as a backup reservoir, is the smallest among the seven lakes and is known for overflowing quickly during intense monsoon spells due to its limited catchment area.
Tulsi Lake only supplies water to the Goregaon area of the Western suburbs of Mumbai
However, the majority of Mumbai's water comes from massive reservoirs located outside the city.
Located in Shahapur, Thane district, the Bhatsa Dam is the largest contributor to Mumbai's water supply, meeting nearly half of the city's daily requirement. Apart from supplying drinking water, the reservoir also supports hydroelectric power generation.
Other major external sources include:
Upper Vaitarna: One of Mumbai's largest storage reservoirs, located in the Nashik-Thane region.
Middle Vaitarna: Commissioned in 2012 to bridge the city's growing water demand.
Modak Sagar (Lower Vaitarna): Built on the Vaitarna River in the 1950s and serves as a major water storage and settling point.
Tansa Lake: Commissioned in 1892 in Thane district, known for its massive dam structure and overflow gates during the monsoon.
Contrary to popular belief, there is no direct pipeline connecting a single lake to a particular neighbourhood. Instead, water from the seven sources is channelled through two major distribution networks after treatment.
Source lakes: Upper Vaitarna, Middle Vaitarna, Modak Sagar and Tansa
Treatment hub: Bhandup Water Treatment Plant
This network mainly supplies the Western Suburbs and parts of South Mumbai.
Areas served include:
Dahisar
Borivali
Kandivali
Malad
Goregaon
Jogeshwari
Andheri
Vile Parle
Santacruz
Khar
Bandra
Source lakes: Bhatsa Reservoir, along with support from Vihar and Tulsi lakes
Treatment hub: Panjarpur/Pise Treatment Plant
This network primarily supplies the Eastern Suburbs and central parts of Mumbai.
Areas served include:
Mulund
Bhandup
Kanjurmarg
Vikhroli
Ghatkopar
Vidyavihar
Kurla
Parts of Central Mumbai
South Mumbai gets a mixed water supply
The Island City receives water from a combination of the Bhatsa system and the Vaitarna-Tansa network.
Areas including:
Sion
Matunga
Dadar
Wadala
Mahim
Byculla
Mazgaon
Malabar Hill
Girgaon
Fort
Colaba
receive water through interconnected transmission networks.
While Tulsi Lake has a much smaller capacity compared to reservoirs like Bhatsa and Vaitarna, it continues to play a crucial role by supplying select high-elevation areas and institutional zones.
With millions of residents relying on these seven reservoirs, the city's water availability is closely linked to monsoon rainfall. Every year, the rise in lake levels becomes a key indicator of Mumbai's water security, while delayed rains can raise concerns over future supply cuts.
From the hills of Thane and Palghar to the heart of Mumbai, these seven lakes remain the city's hidden lifeline.
