Every summer, Bengaluru goes back to doing what it knows too well — figuring out how to make its water last. The Bengaluru Water Supply and Sewerage Board (BWSSB) puts out its action plan, neighbourhoods brace for tighter days, and tankers begin to fill the gaps. 

But this time, the city is juggling an additional demand, one that doesn’t slow down when the taps do — its data centres, and the water they greedily consume.

That issue now sits at the centre of Karnataka’s push to rewrite its data centre policy. In the Assembly this March, Information Technology (IT) Minister Priyank Kharge warned that data centres were "heavy water and energy guzzlers" and said the state needed a greener approach. He said 1 mega watt (MW) of data centre capacity requires one acre of land and Rs 70 crore in investment. Each mega watt demands 25 million litres of water a year. 

"If you ask five questions on ChatGPT, 500 ml of water is needed," Priyank told legislators. "We have to re-look the existing policy and come up with a sustainable one."

Before the state can draft a sustainable policy, it must answer a question it has not systematically measured: how much water does this industry actually draw?

TNM asked the government how much water the data centres are consuming. And the responses of the water board, the pollution control board, and the IT department revealed why the Minister’s warning has become more urgent than he may have intended. 

Data centres are large facilities that house the servers, storage systems, and networking equipment that power everything from cloud computing to artificial intelligence. They run continuously, generate enormous heat, and require constant cooling, which is why water sits at the centre of their environmental footprint. Karnataka has 32 private data centres, of which 31 are in Bengaluru. 

At the water board (BWSSB), officials confirmed the board has not tracked the water supplied to data centres as a separate category. The chairman Ram Prasath Manohar said the board had only recently been instructed to begin gathering this information.  

“BWSSB doesn't have data because they don't monitor where water is going for commercial purposes,” said Khushbu Birawat, a water and environment consultant. 

At the Karnataka State Pollution Control Board (KSPCB), which oversees environmental clearances and compliance, multiple officials could not quantify a data centre's water needs. The board has no consolidated accounting of cooling water permissions or consumption norms for the sector.

The IT department, after repeated follow-ups, offered an estimate of roughly 4,000 kilolitres per day across all 32 facilities in the state. But the data was only an industry-wide approximation assembled through informal conversations with operators.

Independent researchers put the consumption figure considerably higher than the government's estimate.

Shashank Palur, a hydrologist at WELL Labs, calculated that Bengaluru's data centres consume approximately 20 million litres per day. The methodology is grounded in publicly available data: one megawatt of data centre capacity requires approximately 26 million litres of water per year. According to the IT department, 18 of Karnataka’s 32 centres alone account for 292.27 MW.

Globally, the sector is under growing scrutiny. In the United States of America, Google, Amazon, and Meta have faced community opposition and regulatory pressure over the volumes of water their facilities draw from local sources, with some towns in drought-prone states pushing back against new approvals........

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