Five million US gallons is about 18.9 million litres. At that daily rate, a large data centre would require a water supply comparable to a town’s, bringing its cooling requirements into the same planning decisions as homes, businesses and river flows.
The figure is a high-end published estimate, not a typical facility’s measured demand. Actual use varies enormously with size, weather and cooling design. The expansion into places with limited water supplies makes those differences more consequential.
What the five-million-gallon estimate means
The Environmental and Energy Study Institute’s June 2025 briefing cites potential use of up to five million gallons daily by large centres, comparing it with a town of 10,000 to 50,000 people. The headline’s 50,000-person comparison corresponds to 100 US gallons per person per day. It represents broader daily demand, not drinking water alone.
A September 2026 Pacific Institute review by Heather Cooley and Morgan Shimabuku provides a useful check against reported data. Across 65 facilities, average daily withdrawals calculated from annual records ranged from about 270 gallons to 3.9 million gallons. The median was approximately 121,000 gallons.
Those records cover 2024 or 2025. They do not consistently distinguish individual buildings from campuses, and annual averages conceal hotter days with higher demand. Five million gallons should therefore be read as a possible high-end scale, not a verified daily reading for an identified building or a value to multiply by every data centre.
Withdrawal and consumption describe different things
A water bill records supply delivered to a site. Its environmental consequences depend partly on how much returns to the local water system and how much becomes unavailable for immediate reuse.
The US Geological Survey distinguishes withdrawal from consumptive use, which includes water lost through evaporation. Water can circulate repeatedly through cooling equipment while still requiring replacement as some evaporates.
The water has not vanished from the planet.
It has, however, left the local supply in a form that cannot immediately flow to another customer or sustain the same stretch of river. That difference explains why describing all cooling water as permanently destroyed is wrong, but saying the water cycle makes local consumption irrelevant is also wrong.
Equally, a liquid-cooled chip does not by itself establish how much freshwater a whole facility needs. Heat must ultimately leave the building, and the equipment performing that final step determines whether evaporation is involved.
Water scarcity can change a project’s design
The Pacific Institute review describes expansion into water-scarce and rural areas, where new industrial demand can challenge local infrastructure. A site’s electricity connection, land and communications access can look attractive even when the available water supply is limited.
Google’s Mesa project illustrates why the cooling details matter. In a December 2023 account of its own planning process, Google said the Arizona site’s water source faced a high risk of scarcity and depletion. It chose air cooling in response.
That is a company description of its decision, rather than an independent audit of its environmental performance. It nevertheless documents both the attraction of a water-stressed location and a design choice intended to limit the project’s water demand.
A facility in a dry region does not automatically use five million gallons a day, and choosing lower-water cooling does not erase every other infrastructure requirement.
Summer peaks can matter more than annual totals
A March 2026 assessment from the Interstate Commission on the Potomac River Basin shows why annual figures can miss the operational difficulty. It estimated data centres’ average consumptive use within the Washington metropolitan area at approximately four million gallons a day in 2025, with peak-day use around 15 million gallons.
Those are regional totals, not measurements for one centre. The assessment draws on aggregated utility records and estimates for locations without direct reporting.
The commission found current average impacts relatively modest, but highlighted summer demand arriving when river flows are lower and competing uses are higher. Under its baseline assumptions, average metropolitan consumption could reach around 22 million gallons daily by 2050, with peaks above 80 million. Cooling choices and the amount of development actually built could change that forecast.
The same assessment notes that reclaimed water can reduce demand for drinking-water supplies while still reducing river return flows if it evaporates. Reuse changes the source of the water; it does not necessarily eliminate consumption.
Cooling choices also affect electricity demand
SpaceDaily’s earlier coverage of AI demand, solar construction and natural-gas generation examined the electricity side of this expansion. Water accounting adds another consideration because generating electricity can itself require water.
In a 2025 Nature life-cycle assessment, Husam Alissa and colleagues compared cooling approaches across cloud infrastructure. The study, involving Microsoft and WSP researchers, estimated reductions in blue-water consumption, meaning surface water and groundwater, of 31 to 52 per cent for the advanced cooling configurations assessed. These were results for particular systems and assumptions, not guaranteed savings at every centre.
SpaceDaily has also examined how terrestrial infrastructure delays shape proposals for orbital computing. Water constraints belong in that discussion, but a proposed alternative still needs to demonstrate its capacity, costs and thermal performance.
For a community assessing a new campus, the decisive information is more specific than a town-sized comparison: expected average and peak withdrawals, consumptive losses, water source, cooling method and drought arrangements. The five-million-gallon estimate conveys scale. Daily and seasonal disclosures are needed to assess whether a particular development can be supplied through a drought.