The building that drinks: India's data centres and the water nobody meters

It is April in east Bengaluru. The society WhatsApp group pings before breakfast: supply is short again, the tanker has been booked, please store water. Down the road, past Whitefield, sits a building with no balconies, no residents and almost no windows. It runs every hour of every day, and the state's own data centre policy promises to help it get water around the clock.

That building is a data centre, and this is a map of where India has chosen to put them: inside the cities that are already running dry, with a water bill that, until three weeks ago, no Indian rule asked any data centre to disclose, building by building.

Thirty-two buildings, two numbers

Start in Bengaluru, because Bengaluru is where someone finally asked. Karnataka has 32 private data centres, and 31 of them are in Bengaluru, clustered in the eastern and south-eastern corridors of Whitefield and Electronic City, with newer ones pushing out towards Devanahalli, according to reporting by The News Minute, published in Newslaundry in April 2026.

The reporters asked the water board how much these buildings draw. The Bengaluru Water Supply and Sewerage Board said it had never tracked data centres as a separate category. The state pollution control board could not quantify it either. The IT department, after repeated follow-ups, offered roughly 4,000 kilolitres a day across all 32 facilities, an approximation assembled from informal conversations with operators.

An independent hydrologist, Shashank Palur of WELL Labs, worked from published capacity and a standard intensity figure and arrived at about 20 million litres a day for Bengaluru's data centres alone. That is five times the state's number. Both are estimates. Neither is a meter reading.

The ground under that belt is already overdrawn. The same report cites the Central Ground Water Board finding that Bengaluru extracts almost ten times what it recharges each year, and that Devanahalli, which has no perennial surface water source, is drawing 169% of its permissible extraction limit. Meanwhile Karnataka's Data Centre Policy 2022-2027 says the state "would facilitate provision of uninterrupted water supply (24*7)" to data centre units.

Why India's heat pushes the industry towards water

A data centre is a machine for turning electricity into heat, with some computing along the way. Every watt the servers draw has to be carried out of the building. There are two broad ways to do it.

Air-cooled chillers reject heat to the outside air and use little or no water, but they burn more electricity. Water-based systems, such as cooling towers, evaporate water to carry the heat off; they are more energy-efficient and far thirstier. The Council on Energy, Environment and Water (CEEW), in its February 2026 white paper, notes that high ambient temperatures and humidity in tropical regions reduce the efficiency of air cooling compared with mild climates. India's weather tilts the economics towards water. Down To Earth reports that most Indian data centres use evaporative cooling and that roughly 80% of that water evaporates and is lost.

The racks are getting hotter. CEEW records average rack density rising from about 1–3 kW in the early 2000s to around 8 kW today. AI hardware runs far denser. And CEEW, citing the International Energy Agency, puts the on-site cooling demand of a typical 100 MW hyperscale campus at about 2 million litres a day.

The national number is a model, and the industry disputes it

The figure most often quoted for India's whole sector is about 150 billion litres a year, rising to about 358 billion by 2030. Read the footnote. CEEW attributes the 150 billion figure to Mordor Intelligence, a market-research firm, and it is a modelled estimate: capacity multiplied by an assumed water intensity. No Indian operator publishes a metered, facility-level water figure that would let anyone check it.

The operators say the model is wrong in their favour. "The concerns are overstated," Sunil Gupta, chief executive of Yotta Data Services, told a Business Standard webinar in August. "In India, as an industry, we are not using the water-cooled chillers at all." Yotta, CtrlS and Equinix told the paper they use air-cooled chillers with water in a closed loop. Sify told BusinessLine it standardised on air-cooled closed-loop chillers five years ago. Google says its Visakhapatnam campus will be air-cooled.

Take them at their word, and two things still follow. Air cooling trades water on site for electricity, and a coal or nuclear plant needs water to make that electricity; Outlook, summarising material presented at February's AI Impact Summit, notes that this off-site water can exceed what the data centre itself uses. And a claim is not a meter. The most telling line in the whole debate came from Google's own Alexander Smith, speaking to Business Standard: "Sometimes these concerns come because there is no transparency in reporting."

The industry's own stakeholders, consulted by CEEW, rated future water risk as "low to medium". The cities they are building in tell a different story.

The map runs through the driest pipes

Pull back from Bengaluru to the national map. In a Lok Sabha answer in March 2026, the electronics ministry tabled operational capacity by city, from industry sources: Mumbai and Navi Mumbai 790 MW, Chennai 305 MW, Bengaluru 182 MW, Hyderabad 152 MW, Delhi-NCR 76 MW. CEEW counts more than 65% of India's data centres in six regions. Every city on that list shares its water with crores of residents.

Move the camera south-east. Chennai, the second-largest cluster, hit what Down To Earth calls "Day Zero" in 2019, when its four main reservoirs fell below 1% of capacity. Up the Deccan, Hyderabad faces a projected water deficit of 870 million litres a day by 2027, the same magazine reports. Then the weather turned. The India Meteorological Department's end-of-season statement puts the 2026 southwest monsoon at 87% of the long-period average, the fourth-lowest since 2001. The South Peninsula, home to Chennai, Bengaluru and Hyderabad, received 76%, its fourth-lowest since 1901.

Under all of it sits the national arithmetic. India has more than 18% of the world's population and about 4% of its renewable water resources, a figure the Vice President cited in a 2020 government release and which CEEW attributes to the World Bank.

The way out is already built, somewhere

None of this is a technology problem. Closed-loop systems recirculate the same water. ESDS told BusinessLine its Mumbai facility tops up only 2,500 to 3,000 litres a year, a company figure no regulator has audited. Direct-to-chip and immersion cooling cut water further; CEEW says adoption is slow because of cost, thin vendor choice and maintenance complexity.

The sea is the other exit. Andhra Pradesh's data centre policy actively promotes seawater cooling for coastal sites, CEEW notes. Reliance's Jio says its new 168 MW facility at Jamnagar will be cooled with desalinated seawater and run on renewable power. Greyhound Research, which welcomed the move, added the caveat that matters: desalination needs energy and intake systems, and it leaves brine. "It must be measured, reported and audited rather than wrapped in a green ribbon and waved through."

Rajasthan has gone furthest on paper. CEEW calls its 2025 policy India's most comprehensive sustainability-oriented data centre framework, with mandatory wastewater recycling, zero liquid discharge, rainwater harvesting and groundwater recharge. It is a desert state writing the water rules the coastal and southern states did not, until this autumn.

Who has to tell you how much

In the European Union, the revised Energy Efficiency Directive of 2023 requires data centres above 500 kW to report their energy and water use, CEEW notes; on 21 September 2026 the European Commission proposed a common rating scheme to make that use comparable across sites.

In India, the answer was nobody. In a Rajya Sabha reply on 6 August 2026, the environment ministry confirmed that AI data centres do not, per se, require environmental clearance; they need one only when the building crosses general construction thresholds, such as 20,000 square metres of built-up area. The Hindu found in September that none of the state data centre policies required public disclosure of daily water consumption.

Then, in a fortnight, the ground moved. On 30 September, Karnataka issued a Sustainable Data Centre Policy 2026–2031 that, The News Minute reports, will require data centres to report Water Usage Effectiveness plant by plant, reimburses up to ₹30 lakh a year in water charges for units holding WUE between 0.7 and 1.3 litres per kWh, and pays for treated water. On 14 October, NITI Aayog's Frontier Tech Hub published a framework for states that asks for certified meters and periodic reporting in high-stress locations, and for BEE, BIS and MeitY to standardise how WUE is measured. NITI is explicit that the framework is meant to support decisions, "not prescribe a uniform approach or create an additional layer of regulation".

So the truth, as of this week: one state has written a reporting requirement whose operational guidelines are still to come, and the national body has written advice. The water itself remains unmetered in public.

What to watch

The horizon here is close. Karnataka's operational guidelines will show whether "will have to report" means a public number or a file in a department. MeitY's minister of state, Jitin Prasada, said on 14 October that a dedicated national data centre policy is being prepared, the Indian Express reported; whether it carries a WUE line is the test. Karnataka is also planning data centre parks at Hoskote, Mangaluru and Mysuru, and the Hoskote plan, per The News Minute, leans on 60 million litres a day of secondary treated water rather than the city's pipes.

Summer will return to the South Peninsula next April, after a 76% monsoon. The society group will ping again. The question is whether, by then, the building down the road has to tell anyone what it drank.