Water at metropolitan scale: How Mumbai came to dominate regional water resources

Mumbai's water story is often framed as one of scarcity. Yet across the Mumbai Metropolitan Region (MMR), a striking imbalance shapes everyday access to water. While residents of Vasai Virar, Bhiwandi Nizampur and Mira Bhayandar receive only about 70, 100 and 105 litres per capita per day (lpcd), respectively, well below the CPHEEO benchmark of 135 lpcd, Mumbai residents consume around 252 lpcd [1]. The city alone accounts for nearly 67 percent of the region's water resources.

Around 97% of Mumbai’s water originates from dams on the mainland, outside Mumbai's municipal boundaries and often closer to neighbouring municipalities that continue to face persistent shortages. This raises a simple but rarely asked question: how does a city located on an island secure such large quantities of water while surrounding urban centres struggle to meet even basic demand?

Planning the region’s water: The origins of the Mumbai Hydrometric Area

This story can be traced back to the 1960s, when the Government of Maharashtra appointed the British consulting firm Binnie & Partners (B&P) to assess and plan water resources for Mumbai and the wider metropolitan region. In their assessment, the consultants expressed concern over the rising future demand for water from growing urban and industrial centres and their aspirations of developing independent water resources.

This concern was not unfounded. Several agencies had already begun moving in this direction, planning their own water sources. The Maharashtra Industrial Development Corporation (MIDC), for instance, was preparing projects such as the Ransai and Barvi dams to meet industrial demand. The state Irrigation Department had initiated the Upper Vaitarna hydropower scheme and was planning the Bhatsa dam. At the same time, the City and Industrial Development Corporation (CIDCO) were assessing water resources for a proposed ‘twin city’, now Navi Mumbai.

This created a fragmented landscape, with multiple actors competing for limited water resources. Consultants B&P identified this as a critical concern: that such competing demands could reduce Mumbai’s future access to water from the mainland.

In response, they proposed a reorganisation of the region’s water geography. They recommended defining a new planning unit—the Mumbai Hydrometric Area (MHA)—covering the Vaitarna and Ulhas river basins, along with rivers draining into Dharamtar Creek, to enable integrated management of water resources across the region (Figure 1). This approach, based on managing water along hydrological boundaries or river basins, was widely seen as scientific, efficient and modern. It promised coordinated planning and optimal use of scarce resources. However, the implications of this move were far from neutral.

The World Bank and the push for regional water planning

At the same time, the World Bank was negotiating financial support with the Brihanmumbai Municipal Corporation (BMC) for what later became the Bombay Water Supply and Sewerage Project (BWSSP). In its assessment, the Bank highlighted a similar concern: that water planning failed to recognise the interdependence between the city and its mainland sources. 

Recognising this interdependence, the World Bank strengthened the case for a regional, basin-based approach to water planning. While evaluating the BWSSP, the World Bank emphasised the need for coordinated development of water resources across the region and supported the idea of the Mumbai Hydrometric Area (MHA). It also pushed for the creation of a regional planning authority. 

The Bank argued that water planning for Mumbai was not possible without coordinated and controlled development of mainland resources. Accordingly, when financing the BWSSP in 1973, it included a loan condition requiring the establishment of a regional water resources authority for the MHA [3].

In 1975, this led to the creation of the Water Resources Management Board (WRMB) within the Mumbai Metropolitan Region Development Authority (MMRDA), tasked with managing water resources along the hydrological boundaries of the MHA. Covering a total area of 11,590 km², the MHA encompasses the entire MMR and includes hundreds of villages located beyond the metropolitan region in four neighbouring districts.

From integration to allocation

Following the adoption of the MHA, the Board engaged a range of experts and commissioned several studies to assess the region’s water resources. In 1983, it prepared a Perspective Plan outlining the development of water resources across the metropolitan region [4].

However, rather than creating an integrated regional system, the plan ultimately allocated water resources to individual municipal corporations and councils. Over time, this effectively reduced a regional planning vision to a system of allocation. The MMRDA Act was subsequently amended, and the Board was eventually dissolved. Despite this, the process of assessing water resource potential across the entire MHA remained a significant contribution. It provided a basis for understanding and allocating regional water resources.

According to the former Chief Planner of MMRDA, as a planning agency, MMRDA’s role remained largely limited to preparing plans rather than implementing them, which would have required substantial financial investment. As a result, the idea of developing water resources at a regional scale was abandoned, and responsibility for development was effectively passed on to individual municipal corporations and councils.

How planning enabled control

The shift from integrated planning to allocation had important consequences. Through the process of defining MHA, assessing its water resources, and allocating them among municipal bodies, Mumbai secured legitimate access to water resources located on the mainland, beyond its jurisdiction.

The MHA spans a vast stretch of the mainland, far beyond the city’s municipal limits. Ironically, Mumbai itself—situated on an island—does not lie within this hydrological region. Yet the area was named after the city. By defining and organising this region in Mumbai’s name, planners created a basis for planning, allocating, and ultimately securing mainland water resources for Mumbai.

As part of this process, the Board specifically allotted water to Mumbai and granted it permission to develop three major dams—Middle Vaitarna, Kalu and Gargai—to meet its future demand. In doing so, it effectively addressed the concern raised decades earlier by Binnie & Partners regarding the need to recognise Mumbai’s dependence on mainland water sources.

Mumbai subsequently developed the Middle Vaitarna dam and is now moving ahead with Gargai. There is, however, another twist in this story. Instead of developing the Kalu dam as originally planned, the city chose to pursue the Pinjal dam and focused on the Damanganga–Pinjal river-linking project.

Table 1: Key milestones in the evolution of the Mumbai Hydrometric Area and regional water planning

A strategic shift: Pinjal over Kalu

Although the Kalu dam had been allotted to Mumbai, the city later revised its plans. In 1999, while preparing its master plan, BMC chose to replace the Kalu project with the Pinjal dam [5]. Notably, Pinjal had originally been allocated to the Vasai-Virar Municipal Corporation and nearby villages in the northern part of the metropolitan region.

The choice between the two sites was shaped by technical and economic considerations. The Kalu dam, located in the Ulhas basin, would have required pumping water to Mumbai due to elevation differences. In contrast, water from the Pinjal dam, located in the Vaitarna basin, could be supplied by gravity.

This made Pinjal a more attractive option. It avoided the need for pumping, reduced operational costs, and ensured a more reliable supply without dependence on electricity. The Vaitarna basin was also less densely populated and less prone to pollution at the source compared to the Ulhas basin. As a result, water from Pinjal, the Damanganga-Pinjal link, was expected to be of better quality, reducing treatment requirements. In effect, Mumbai gave up an already allotted source in favour of one that offered greater reliability, lower costs and better water quality.

Response of the World Bank

Although the World Bank had promoted an integrated, basin-based approach to water planning, this vision was not sustained in practice. Even after the approach was effectively abandoned in 1983 and the Board was dissolved, the Bank continued to fund the ongoing phases of the BWSSP, including Phase II and later Phase III in 1986.

This suggests that the integrated approach to river basin planning was only partially implemented. While it shaped the initial assessment and allocation of water resources, it was not sustained through institutional practice.

Rethinking water governance at the metropolitan scale

The Mumbai Hydrometric Area was introduced as a scientific solution to the problem of managing water across a rapidly urbanising region. By organising water resources along hydrological boundaries rather than administrative ones, it promised efficiency, coordination and rational planning. Yet beneath this technical language lay a more consequential transformation: it created the conditions through which Mumbai's growing claim over regional water resources came to appear both natural and unquestionable.

In theory, the framework sought to manage a shared resource. In practice, it enabled Mumbai to secure long-term access to future water sources on the mainland and selectively prioritise those that offered the greatest strategic advantages, including higher elevations that reduced pumping costs and catchments less vulnerable to present and future pollution. What emerged was not simply a plan for managing water but a geography of preferential access.

The consequences continue to shape the metropolitan region today. Backed by its financial resources and institutional capacity, Mumbai could identify, reserve and develop water sources on its own terms and timelines. Many neighbouring municipal corporations and councils lacked similar capacities and struggled to develop their own supplies. Meanwhile, Mumbai commissioned the Middle Vaitarna dam in 2014. In April 2026, the BMC's Standing Committee approved the Gargai dam project at an estimated cost of ₹5,000 crore, while the Damanganga–Pinjal river-linking project remains under preparation. Several neighbouring urban local bodies continue to face chronic water deficits. The inequalities embedded in earlier planning decisions are therefore not historical artefacts; they continue to structure water access in the region today.

The story extends beyond cities. Thousands of villages located within the Mumbai Metropolitan Region and the Mumbai Hydrometric Area remained largely absent from planning decisions, despite living closest to the rivers, reservoirs and dam sites that sustain the metropolis. Many continue to face routine shortages even as water from their landscapes is transferred elsewhere. In this sense, scarcity is not simply a product of nature or limited resources. It is also produced through planning decisions that determine whose claims are recognised and whose are overlooked.

This raises a larger question about metropolitan water governance. When a city draws water from distant territories, who gets to decide how those resources are allocated? Who benefits from regional planning, and who bears its costs? The history of the Mumbai Hydrometric Area suggests that maps, planning boundaries and technical assessments are never merely administrative tools. They shape access, privilege certain futures over others and influence who receives water, how much they receive, and at what quality.

Water debates in India are often framed as conflicts between urban and rural areas or as inequalities within cities. Far less attention is paid to the metropolitan scale, where multiple cities, towns and villages compete for the same rivers, reservoirs and aquifers. Yet it is at this scale that some of the most important decisions about water allocation are made.

If Mumbai's experience reveals anything, it is that the central question is not whether enough water exists. It is how societies choose to distribute it. The future of metropolitan water governance may depend less on finding new sources of water than on confronting the politics hidden within the systems designed to manage it.

References

1. MMRDA. (2021). Final regional plan for Mumbai Metropolitan Region. Mumbai Metropolitan Planning Committee, Mumbai Metropolitan Region Development Authority.

2. World Bank. (1973a). Appraisal of Bombay Water Supply and Sewerage Project, India. India: World Bank.

3. World Bank. (1973b). Maharashtra Agreement (Bombay Water Supply and Sewerage Project) between the Governor of the state of Maharashtra and the International Development Association (Credit Number 390 IN): World Bank.

4. BMRDA. (1985). Hydrology of Bombay Hydrometric Area. Mumbai: Bombay Metropolitan Region Development Authority.

5. BMC (1999). Master plan for the water supply of Mumbai (For its growth by the year 2021). Executive Engineer, Water Works Planning and Research, Hydraulic Engineer’s Department, Brihanmumbai Municipal Corporation.