Public water supplies in America will need billions invested to meet the peak requirements of datacenters during the hottest periods of the year, even if their overall annual consumption is relatively modest.
A study by researchers at the University of California, Riverside, acknowledges that water is an efficient means of cooling for server farms, which are looking to minimize their power usage.
But it warns that the growing water demand will lead to substantial peak withdrawals, which many communities in the US do not have the capacity to supply, particularly during the hottest days of the year.
Without new water efficiencies, datacenters across America may require 697 million to 1.45 billion gallons of extra peak water capacity per day by 2030, the study estimates. This compares with New York City’s daily water supply of about a billion gallons.
Not like we have any other uses for water in a rapidly heating world.



New York City is a port city. It has an effectively infinite supply of salt water, which you can use for evaporative cooling, albeit with some extra complications.
EDIT: Hell, you can use the waste energy from an evaporative cooler to drive a distiller to generate fresh water from some of the evaporated salt water, if you want. Microsoft is doing that combined datacenter-nuclear-power-plant thing. IIRC, if I’m not combining two different cases of an AI datacenter using full output of a power plant, they have the entire output of a nuclear power plant never touching the grid (and thus avoiding any transmission cost overhead and as a bonus, avoiding regulatory requirements attached to transmission and distribution from power generation):
https://arstechnica.com/ai/2024/09/re-opened-three-mile-island-will-power-ai-data-centers-under-new-deal/
From past reading, desalination from reverse osmosis has wound up being somewhat cheaper than via using distillation, but combined generation-distillation using waste heat is a thing. IIRC Spain has some company that does combined generation-distillation facilities.
And in a case like that, you have the waste heat from generation and the waste heat from use all in one spot, so you’ve got a lot of water vapor to condense.
EDIT2: Yeah, apparently distillation used to be ahead for desalination, but reverse osmosis processes improved, and currently hold the lead:
https://www.sciencedirect.com/science/article/pii/S1359431124026292
They could also use treated waste water for cooling the data centers instead of dumping it in the ocean.