The data centers that process the world’s cloud computing, streaming video, and AI workloads require two things in industrial quantities: electricity and water. The electricity demand is highly visible — it shows up in grid capacity studies, utility rate cases, and energy policy debates. The water demand is less discussed, harder to track, and in some communities creating conflicts that will only intensify as development accelerates.
A single large hyperscaler campus can consume between one and five million gallons of water per day, according to the Environmental and Energy Study Institute. At the upper end, that is equivalent to the daily water consumption of a town of 30,000 to 50,000 people — drawn from the same municipal systems, or the same aquifers, or the same river, that communities depend on for residential and agricultural use.
How Data Centers Use Water
The primary mechanism of water use in data centers is evaporative cooling. Servers generate heat as a byproduct of computation. That heat must be removed continuously or the equipment fails. The most energy-efficient and widely used method of removing that heat at scale is evaporative cooling: hot water from the server hall is pumped to cooling towers on the roof or in adjacent yards, where large fans blow air across the water, causing a portion of it to evaporate. As water evaporates, it carries heat away from the system. The remaining, slightly cooler water is recirculated. The evaporated water is gone — it is released as water vapor into the atmosphere and does not return to the source.
This is the critical distinction between water consumption and water withdrawal. Water withdrawal is any taking of water from a source, regardless of whether it is returned. Water consumption is water that is taken and not returned — water that leaves the system. Municipal water treatment plants withdraw water, treat it, and discharge it; most of the water is returned to the watershed. Evaporative cooling in a data center withdraws water and consumes nearly all of it. Only a small fraction of the water circulated through a cooling tower is “blown down” — periodically discharged to remove accumulated minerals — and even that fraction must be disposed of, not simply returned to the source.
The practical implication is that a large data center consuming one million gallons of water per day is removing that water from the local supply and not returning it. In regions where water supply is limited — either by precipitation, aquifer capacity, or legal allocation — this matters differently than it does in regions with abundant supply.
How Much Water, and Why Climate Matters
The amount of water a data center consumes for evaporative cooling is not fixed. It depends heavily on the local climate. In hot, dry climates, the efficiency of evaporative cooling is maximized: dry air readily absorbs moisture, so cooling towers can remove heat effectively. But the tradeoff is high water consumption: the facility must evaporate more water per unit of heat removed. A large hyperscaler campus in Phoenix will consume substantially more water for the same computing load than a comparable facility in a cooler, more humid climate like the Pacific Northwest or the upper Midwest, where the cooling system can often achieve acceptable temperatures with less evaporation.
This inverse relationship between cooling efficiency and water consumption — dry air cools well but demands water — is one reason why data center growth in the American Southwest has created particular concern. The region is already water-constrained, aquifers are being drawn down in many areas, and the allocation of water rights among agricultural, municipal, and industrial uses is a long-running source of legal and political conflict.
Industry metrics for water efficiency include the Water Usage Effectiveness (WUE) measure, expressed as liters of water consumed per kilowatt-hour of IT energy. According to EESI, the average WUE across data centers is approximately 1.9 liters per kWh, though efficient facilities aim substantially lower and older or less-well-designed facilities in hot climates can exceed this significantly.
Aggregated nationally, U.S. data centers consumed an estimated 449 million gallons of water per day for direct cooling in 2021, with total figures — including indirect water consumption from the power plants that generate their electricity — substantially higher. As data center electricity consumption is projected to roughly double or triple by 2028 according to Lawrence Berkeley National Laboratory, water consumption will grow in parallel unless cooling technologies change significantly.
The Phoenix Metro and the Arizona Water Question
Arizona has more than 150 data centers and chip manufacturing facilities, concentrated primarily in the Phoenix metro area. The state’s water situation is well known: it is among the most arid in the country, groundwater aquifers in many areas have been declining for decades, and Arizona relies heavily on the Colorado River — a system that is itself overallocated and under persistent pressure.
An analysis by Ceres, a sustainability advocacy organization, estimated that data centers active in the Phoenix metro consumed approximately 385 million gallons of water in a single year. Projected growth could increase that figure tenfold, to around 3.8 billion gallons annually. Ceres also projected that power-plant water usage in Arizona could quadruple as new generation is built to serve data center demand — primarily at rural power plants that may rely on groundwater aquifers. That projected power-plant water consumption could reach 14.5 billion gallons annually, concentrated in rural areas where water access is often more constrained than in the city.
The water utilities serving Mesa, Avondale, and the city of Phoenix have each passed ordinances capping water usage for industrial facilities and requiring developers to purchase supplemental water supplies if they exceed those caps — a direct regulatory response to data center water demand. These ordinances represent an important precedent: they acknowledge that data center water use requires specific policy tools, and they create a mechanism through which communities can constrain growth that would otherwise exhaust local water supplies.
The Columbia River Basin
The Pacific Northwest — Oregon and Washington state — has historically been a preferred location for data centers partly because of its cooler climate (reducing cooling costs and water use), cheap hydroelectric power, and available land. The Columbia River basin hosts a significant and growing concentration of data center facilities, particularly in eastern Oregon and Washington.
Columbia Riverkeeper issued a report in early 2026 documenting the energy and water impacts of over 100 data centers at various stages of development in 12 counties along the Columbia River. The organization found that projected power and water use from the data center buildout would strain Oregon and Washington’s renewable energy mandates and threaten local water resources and fish and wildlife.
Rolling Stone’s investigation of Amazon data centers in eastern Oregon documented a different type of water impact: data centers extracting water from a local aquifer that was already contaminated with nitrates, contributing the contaminated water to a wastewater system, and then returning it to agricultural fields at concentrations that sometimes exceeded state safety limits by a factor of eight. The mechanism is specific to that community’s wastewater infrastructure, but the broader dynamic — data centers interacting with existing water quality problems in ways that were not anticipated or assessed in advance — illustrates the inadequacy of approval processes that do not require detailed water impact analysis.
In Washington, a proposed data center project in Quincy would have pumped approximately 400 million gallons of water from the Columbia River annually, according to reporting by Stanford’s journalism program — raising concerns among farmers and communities that depend on the same water system.
The Netherlands: A Different Regulatory Response
The European response to data center water and energy demands offers a contrast to the U.S. approach. The Netherlands, a major global hub for data center infrastructure due to its fiber connectivity and position in European internet exchange geography, imposed a moratorium on new hyperscale data center development beginning in 2019. The Amsterdam metropolitan area and surrounding Haarlemmermeer municipality imposed restrictions citing lack of power capacity and concerns about the aggregate demands of the facilities on local infrastructure.
As of 2024, projects with an IT capacity of 70 megawatts or more, or those above 10 hectares in size, remained banned in most of the Netherlands, with limited exceptions in the north of the country. The government’s rationale focused primarily on power capacity, but water and land use were also cited in public debate about the policy. The Netherlands example is notable not because it provides a direct model for U.S. communities — the regulatory frameworks are very different — but because it demonstrates that a national or regional government can conclude that unrestricted data center development is inconsistent with infrastructure constraints and impose moratoriums accordingly.
Where the Water Comes From and Who Issues Permits
In the United States, data center water typically comes from one of three sources: municipal water systems, groundwater wells, or reclaimed (recycled) water where utilities have developed that infrastructure.
Municipal water systems are the most common source for data centers in developed suburban and urban areas. These systems were designed to serve residential and commercial demand, not industrial-scale evaporative cooling. When a data center draws heavily on a municipal system, it increases the total load on water treatment and distribution infrastructure — potentially accelerating the need for capacity upgrades whose costs are spread across all ratepayers, or reducing the pressure and reliability of service to other users during peak demand periods.
Groundwater wells require permits from state or local water management agencies. In many western states, water rights are a formal legal system separate from land rights: owning land does not automatically entitle you to extract groundwater beneath it. In these states, a new water withdrawal requires a permit, and the permit process may include public notice and opportunities for other water users to object. These permit proceedings — often handled by state water management agencies or water conservancy districts — are underutilized as community engagement opportunities, in part because they are technically specialized and separate from the land use process.
Reclaimed water — treated wastewater reused for cooling — is available from some utilities as an alternative to freshwater withdrawal. Some data center operators have committed to using reclaimed water for cooling, which reduces pressure on freshwater supplies. Whether reclaimed water is available at a given site depends on the local utility’s infrastructure.
The Disclosure Gap
One of the most significant obstacles to community assessment of data center water impacts is the near-total absence of mandatory public reporting on water consumption. Most data centers are not required to disclose how much water they use. The large hyperscalers — Amazon, Microsoft, Google — publish water consumption figures in their annual sustainability reports, but the reported figures are global aggregates, not facility-level disclosures. A community adjacent to a specific facility typically cannot determine from public records how much water that facility is consuming.
The exception is in states and localities where water permits require reporting. Groundwater permit holders in states with active water management agencies may be required to report annual withdrawals. Municipal water customers who use very large quantities may be subject to disclosure requirements or tiered pricing that creates at least partial transparency. But in most jurisdictions, for most facilities, the data is not available.
This means that residents who are concerned about a proposed data center’s water impact face the challenge of working from estimated figures — consumption ranges based on facility size, power demand, and climate — rather than from verified reporting. Requesting, during the permit approval process, that water consumption reporting be made a condition of the conditional use permit is one mechanism through which communities can create disclosure obligations where none otherwise exist.
Environmental and Energy Study Institute: Data Centers and Water Consumption | Grist: Arizona’s Water and the Data Center Rush | Columbia Riverkeeper: Data Center Impacts Along the Columbia | Rolling Stone: Oregon Data Centers and Water Pollution | Data Center Dynamics: Amsterdam Moratorium | Lawrence Berkeley National Laboratory: Data Center Energy Report
This article was researched and drafted with AI assistance under human review. See our full AI and editorial practices.