Who pays for a data center's water
Capacity, not gallons, is what gets built and billed · as of 2026-08-26
- If 2024 water-use intensity persists, U.S. data centers could collectively require 697 to 1,451 million gallons per day of new water capacity through 2030, comparable to New York City's average daily supply of roughly 1,000 MGD. Under an optimistic scenario of 10 percent annual intensity reduction the requirement falls to 227 to 604 MGD. Source: Han, Li, Wierman & Ren, Small Bottle, Big Pipe: Quantifying and Addressing the Impact of Data Centers on Public Water Systems (arXiv 2603.02705)
- The authors put the total valuation of that new water capacity 'on the order of $10 billion, reaching up to $58 billion in the high-growth case', and note the impacts 'are highly concentrated on communities hosting data centers'.
- The binding constraint is peak, not average: meeting data-center demand 'requires substantial peak water withdrawals, which many communities in the United States cannot supply, especially during the hottest days of the year'.
- That peak constraint feeds straight back into the grid. The paper notes it 'can force operators to rely on less efficient dry cooling, further stressing the power grid during summer peaks', which is the same tradeoff this site prices on the water hub.
This site exists to ask who pays for a data center's electricity. The same question applies to its water, and it has a different answer, because water is delivered almost entirely by municipal utilities rather than investor-owned ones. When a data center needs more capacity than a city's pipes and treatment plants can deliver, somebody funds the upgrade, and the default somebody is the city's existing customers.
The bill is for capacity, not gallons
The volume a data center consumes in a year is not what strains a utility. What strains it is the peak: the plant has to be sized for the hottest day, and a facility running evaporative cooling draws hardest exactly when every household is also watering and cooling. That peak is what has to be built, and building it is where the billions go.
The estimate above, $10 billion to $58 billion, is the valuation of new water capacity, not an annual water bill. It is also the clearest published statement that the water question and the electricity question are the same question: when a community cannot supply the peak, operators shift to dry cooling, which raises electricity demand at the summer peak, which is what the capacity auctions price. The water cost of that switch.
What providers now require before they will serve one
Arizona is the most developed example because its providers have had to write these rules first. Thresholds are how each provider defines a large-volume user, not a data-center-specific cap unless stated. Source: Kyl Center for Water Policy, Morrison Institute for Public Policy, ASU: How Arizona Municipal Water Providers Are Regulating Large-Volume Water Users (September 2025)
| Provider | Large-volume threshold | What it requires |
|---|---|---|
| Mesa | 330 acre-feet in a rolling 12 months (new large-meter customers); 550 af for legacy, 850 to 950 af for established legacy | Must apply for a permit, then within 90 days secure and transfer long-term storage credits to the City covering at least three years of the allowance, and maintain that three-year balance. Penalties apply above 105 percent of the ceiling, including higher billing rates and permit revocation. |
| Marana | Data centers specifically | Will not provide potable water to a data center for cooling, humidity control or similar operations; data centers are not a permitted principal use without a specific plan. The developer must bring its own supply. |
| Chandler | Large-meter customers above the Tier I allocation for the land use, or a 3 inch or larger meter | Sustainable water service application at entitlement. If Tier II water is unavailable the user must purchase Tier III water from the City at a price the City sets. |
| Phoenix | At least 250,000 gallons per day, with additional requirements at 500,000 gallons per day | Advance provider approval required. |
| Tempe | 250,000 gallons per day (high use); 500,000 gallons per day or a 3 inch meter (extreme use) | Advance provider approval required. |
| Peoria | 100,000 gallons in any 24 hours, or a 50,000 gallon per day average over 365 days | Advance provider approval required. |
| Avondale | 25,000 gallons per day or 28 acre-feet annually, or peak demand needing a 3 inch or multiple meters | Advance provider approval required. |
| Tucson | Monthly use above an average 10,000 CCF (7,480,520 gallons) | Advance provider approval required. |
| EPCOR (all districts) | Average daily demand above 1,700 gallons per day per acre | Tariff 14 applies. |
Mesa's is the sharpest version of "bring your own water": a permit holder must hand the city long-term storage credits covering three years of its allowance and keep that balance topped up. Marana went further and simply will not sell a data center potable water for cooling at all.
The catch in refusing service
Refusing service does not fully protect a provider. Inside an Active Management Area an applicant may seek a groundwater withdrawal permit for a 'general industrial use'; if the site is within three miles of a provider's service area the applicant must first request service, and if the provider denies it at the customary rate the Director must issue the permit, authorizing withdrawals for up to 50 years subject to renewal. (Ariz. Rev. Stat. sec. 45-515) Source: Kyl Center for Water Policy, Morrison Institute for Public Policy, ASU: How Arizona Municipal Water Providers Are Regulating Large-Volume Water Users (September 2025)
So a city that says no does not necessarily keep the water in the ground. It may simply lose the ability to meter, price or condition the use, while the withdrawal happens anyway on a permit that runs for up to 50 years.
Download the provider rules (CSV) · The electricity equivalent → · Water per kWh by state →