# Data Center Water Usage: How Much and Why > How much water data centers use and why, WUE, direct vs indirect use, water sources, ways to cut use, and the compliance each source brings. Sourced data. Source: https://www.exoduswater.com/post/data-center-water-usage October 30, 2026Exodus Water Services # Data Center Water Usage: How Much Water Data Centers Use, Why, and What It Means for Compliance How much water data centers use and why, WUE, direct vs indirect use, water sources, ways to cut use, and the compliance each source brings. Sourced data. **Short answer:** U.S. data centers consumed about **66 billion liters (about 17 billion gallons) of water on site in 2023** , according to Lawrence Berkeley National Laboratory (LBNL), up from 21.2 billion liters in 2014\. Most of that water evaporates in cooling towers and evaporative coolers. The water used to generate their electricity is far larger, at nearly **800 billion liters** in 2023\. Where the water comes from matters as much as how much is used. Potable water, recycled water, and groundwater each come with their own permits, backflow protection, and testing duties. _Last reviewed October 30, 2026\. Every figure below comes from a report listed in Sources at the end._ ## How much water do data centers use? The most complete national estimate is LBNL’s _2024 United States Data Center Energy Usage Report_ , supported by the U.S. Department of Energy. It models every U.S. data center by type, cooling system, and climate. | Measure | Figure | Source | | ---------------------------------------------------------------- | ------------------------------------------------------- | --------- | | Direct (on-site) water consumption, 2014 | 21.2 billion liters | LBNL 2024 | | Direct (on-site) water consumption, 2023 | 66 billion liters (about 17.4 billion gallons) | LBNL 2024 | | Share of 2023 direct use in hyperscale and colocation facilities | 84% | LBNL 2024 | | Projected direct use by hyperscale data centers alone, 2028 | 60 to 124 billion liters | LBNL 2024 | | Indirect water (power generation), 2023 | Nearly 800 billion liters | LBNL 2024 | | Electricity use, 2023 | 176 TWh, 4.4% of U.S. electricity | LBNL 2024 | | Projected electricity use, 2028 | About 325 to 580 TWh, 6.7% to 12.0% of U.S. electricity | LBNL 2024 | Company reports show the same growth at the operator level. Google reported **10.5 billion gallons of water consumed by its data centers worldwide in 2025** (13.6 billion gallons withdrawn, 3.0 billion gallons discharged). Its total water consumption, including offices, rose 34% from 2024 to 2025\. A single campus can be large: Google’s Council Bluffs, Iowa, site consumed about 1.35 billion gallons in 2025, and its campuses in The Dalles, Oregon, consumed 469 million gallons. **Where sources disagree:** national estimates depend on method and year. A peer-reviewed study by Siddik, Shehabi, and Marston (_Environmental Research Letters_ , 2021) put the total operational water footprint of U.S. data centers in 2018 at 5.13 × 10⁸ cubic meters (513 billion liters), counting both on-site and power plant water. LBNL’s 2023 figures (66 billion liters direct plus nearly 800 billion indirect) use a newer model and a later year. Treat any single national number as an estimate, not a meter reading. ## Why do data centers use so much water? Servers turn the electricity they use into heat, and evaporating water is an energy-efficient way to reject it. **Cooling towers.** In a water-cooled chiller plant, warm water from the chillers runs over a cooling tower, and part of it evaporates. The U.S. Department of Energy’s Federal Energy Management Program (FEMP) explains that tower make-up water equals **evaporation plus blowdown plus drift** : - **Evaporation** is how the tower rejects heat. - **Blowdown** is water drained on purpose, because evaporation leaves dissolved minerals behind and they have to be flushed out before they cause scale and corrosion. - **Drift** is mist carried out of the tower. It is small and controlled with drift eliminators. **Evaporative and adiabatic cooling.** Many large facilities cool with outside air most of the year and add water only on hot days, either by spraying it into the air stream (adiabatic cooling) or by wetting media. LBNL found that facilities using **water-cooled chillers without economizers have the highest water use** , largely from cooling tower water, while airside economizers with occasional adiabatic cooling use very little. **Humidity control.** Meta’s 2025 Sustainability Report notes that most water use in its data centers goes to managing air flow, temperature, and humidity in the server halls. **Growth ahead.** LBNL projects that average on-site water intensity will rise after 2023, reflecting higher WUE in hyperscale and colocation data centers and more water use by liquid-cooled systems. ## What is WUE (water usage effectiveness)? **WUE** is the standard metric for data center water efficiency. It was introduced by The Green Grid as a companion to power usage effectiveness (PUE). As LBNL defines it, WUE is the data center’s **water consumption divided by the electricity used by its IT equipment** , reported in **liters per kilowatt-hour (L/kWh)** . There are two versions: - **Site WUE** counts only water used at the facility, mostly for cooling. - **Source WUE** adds the water consumed to generate the facility’s electricity. | WUE figure | Value | Source | | -------------------------------------------------------------------------------------- | --------------------------------------- | --------- | | U.S. average site WUE, through 2023 | Just over 0.36 L/kWh | LBNL 2024 | | U.S. average site WUE, projected after 2023 | 0.45 to 0.48 L/kWh | LBNL 2024 | | Reported by some hyperscale facilities using airside economizers with adiabatic assist | 0.1 to 0.3 L/kWh | LBNL 2024 | | Microsoft fleet average, fiscal year 2024 | 0.30 L/kWh (down 39% from 0.49 in 2021) | Microsoft | | Water consumed per kWh of electricity supplied to U.S. data centers (indirect), 2023 | 4.52 L/kWh | LBNL 2024 | A low site WUE is not automatically better. LBNL notes that water-cooled systems are generally more energy efficient than air-cooled chillers, which use no water but more electricity. Since power plants also consume water, a facility that saves water on site can raise its indirect water use. ## Direct vs indirect water use | Direct (on-site) | Indirect (off-site) | | | ---------------- | ------------------------------------------------------------ | ----------------------------------------------------------------------- | | What it is | Water the facility withdraws and consumes, mostly in cooling | Water consumed at power plants that generate the facility’s electricity | | U.S. total, 2023 | 66 billion liters | Nearly 800 billion liters | | Main drivers | Cooling system type, climate, operating practices | Grid fuel mix and power plant cooling | | Metric | Site WUE | Source WUE | Nationally, the indirect footprint is roughly 12 times the direct one. But direct use is local: it comes out of the watershed and utility system where the facility sits. Siddik and colleagues found that about **one-fifth of U.S. data center servers’ direct water footprint comes from moderately to highly water-stressed watersheds** , and nearly half of servers are fully or partly powered by plants in water-stressed regions. Google reports that 13% of its 2025 freshwater withdrawals came from sources at high risk of depletion or scarcity, and 15% from sources at medium risk. ## Where does data center water come from? Most data centers buy **potable (drinking) water from the local public water system** . Google’s 2025 data is a useful example of the mix: of 13.6 billion gallons withdrawn by its data centers, about 10.9 billion gallons (81%) was potable water, 1.7 billion gallons was other non-potable water, and 0.9 billion gallons was reclaimed wastewater. | Source | How it is used | Watch-outs | | ---------------------------------------- | ----------------------------------------------------------------- | ----------------------------------------------------------------------- | | Potable water from a public water system | Cooling tower make-up, humidification, domestic use, fire service | Competes with community supply; backflow protection at every connection | | Recycled (reclaimed) water | Cooling tower make-up where approved | Separate piping, use-site approval, cross-connection testing | | Groundwater from an on-site well | Cooling, and sometimes drinking water for staff | A campus well can make the operator a regulated public water system | | Other non-potable water | Cooling where quality allows | Water treatment, separate piping | ## How can data centers reduce water use? The main options in federal and industry sources: 1. **Run cooling towers at higher cycles of concentration.** FEMP says many systems run at two to four cycles, and six or more may be possible. Going from three to six cycles **cuts tower make-up water by 20% and blowdown by 50%** . The practical limit depends on make-up water quality and the treatment program. 2. **Control blowdown carefully.** FEMP identifies blowdown control as the biggest water-saving opportunity in a tower. Conductivity-based controllers and metering on make-up and blowdown lines help. 3. **Use airside economizers.** LBNL found that airside economizers let facilities shut down chilled water systems in favorable weather, saving substantial water. 4. **Switch to closed-loop or chip-level cooling.** Since August 2024, all new Microsoft data center designs use chip-level cooling with a closed loop that does not evaporate water for cooling. Microsoft estimates this avoids more than 125 million liters a year per data center, with a nominal increase in energy use. Pilot sites in Phoenix and Mt. Pleasant, Wisconsin, are planned for 2026. 5. **Use alternative water for make-up.** FEMP lists air handler condensate, once-through cooling water, compatible process effluent, and high-quality recycled water as possible tower make-up sources. 6. **Match cooling to local water risk.** Google applies a water risk framework to its data centers, and the results guide its cooling technology choices. 7. **Meter and budget water.** Meta reports using water budgeting, flow meter audits, and digital twin models of its cooling systems. Some operators also fund watershed replenishment: Google reports about 7.7 billion gallons in 2025, about 78% of its freshwater consumption. Replenishment does not reduce what is drawn from the local system. ## What compliance comes with each water source? Every water source a campus uses creates a regulatory relationship. Rules are set state by state. California examples are labeled as such below. ### Potable water from a public water system - **Backflow protection at the service connection.** Water suppliers enforce cross-connection control programs set by each state. In California, the State Water Board’s Cross-Connection Control Policy Handbook (CCCPH), in effect since July 1, 2024, lists premises with **more than one service connection** , an **auxiliary water supply such as a well** , or **recycled water** as high hazard (Appendix D). - **Cooling towers and chillers** are not named on the California high hazard list. The water supplier assesses them case by case during its hazard assessment. - **Testing.** In California, assemblies are tested at least annually and after installation or repair, and a failed assembly must be repaired or replaced within 30 days (CCCPH 3.3.3). ### Recycled water - In California, Title 22 Section 60306 allows cooling towers to use disinfected tertiary recycled water. Where mist can reach people, a drift eliminator and a biocide to control Legionella are required. - Dual-plumbed sites in California need an annual inspection and a cross-connection test at least every four years (22 CCR 60316). ### Groundwater from an on-site well - Under federal rules (40 CFR 141.2), a system that serves water for human consumption to an average of **25 or more people a day for at least 60 days a year** , or has **15 or more service connections** , is a public water system. Serve the same 25 or more people for more than six months a year and it is a **nontransient noncommunity** system, with permit, monitoring, and reporting duties. - A well connected to a campus that also takes utility water is an auxiliary supply, which California treats as high hazard for backflow purposes. ### Construction and new reporting rules - Clearing, grading, or excavating **one acre or more** needs Clean Water Act stormwater permit coverage (40 CFR 122.26(b)(15)). - In California, Governor Newsom signed AB 2469, AB 2619, and AB 1577 on September 21, 2026, adding data center water disclosure and reporting requirements. Check the final bill text for effective dates and thresholds. For a site-by-site map of these obligations, see [data center water services](https://www.exoduswater.com/data-center-water-services) . ## Frequently asked questions **How much water does a data center use per day?**It varies widely by size, cooling system, and climate, so there is no single answer. For scale, Google’s Council Bluffs, Iowa, campus consumed about 1.35 billion gallons in 2025, roughly 3.7 million gallons a day on average. **What is a good WUE for a data center?**LBNL puts the U.S. average site WUE just over 0.36 L/kWh through 2023\. Microsoft reported 0.30 L/kWh for fiscal year 2024\. A lower site WUE can mean higher energy use, so compare WUE together with PUE. **Why do data centers use water instead of air for cooling?**Evaporative cooling usually takes less electricity than air-cooled chillers. LBNL and Google both note that water-cooled systems are generally more energy efficient, which is why operators weigh water against energy at each site. **Do data centers use drinking water?**Often, yes. Most buy potable water from the local utility. In Google’s 2025 data, about 81% of data center water withdrawals were potable water, with the rest non-potable or reclaimed wastewater. **Do data centers need backflow protection?**In most cases, yes. Water suppliers protect the public system through state and local cross-connection programs. California lists premises with more than one service connection, an auxiliary supply such as a well, or recycled water as high hazard. ## Talk to an expert Exodus Water Services plans, permits, operates, and keeps records for the water systems data center campuses depend on: backflow protection and testing, hazard assessments, recycled water use sites, campus wells, and stormwater. [Talk to an Expert](https://www.exoduswater.com/data-center-water-services#talk-to-an-expert) about your site. Last reviewed: October 30, 2026. ## Sources - Lawrence Berkeley National Laboratory, Shehabi et al., [2024 United States Data Center Energy Usage Report](https://escholarship.org/uc/item/32d6m0d1) (December 2024): executive summary, Section 4 (PUE and WUE modeling), Section 5 (direct and indirect water consumption) - The Green Grid, [WP#35: Water Usage Effectiveness (WUE), A Green Grid Data Center Sustainability Metric](https://www.thegreengrid.org/product/114) - Siddik, Shehabi, and Marston, [The environmental footprint of data centers in the United States](https://iopscience.iop.org/article/10.1088/1748-9326/abfba1) , _Environmental Research Letters_ 16 (2021) 064017 - U.S. Department of Energy, FEMP, [Best Management Practice #10: Cooling Tower Management](https://www.energy.gov/cmei/femp/best-management-practice-10-cooling-tower-management) - Google, [2026 Environmental Report (FY2025 data)](https://sustainability.google/google-2026-environmental-report/) , water data tables and water stewardship section ([PDF](https://sustainability.google/files/google-2026-environmental-report.pdf) ) - Microsoft, [Sustainable by design: Next-generation datacenters consume zero water for cooling](https://www.microsoft.com/en-us/microsoft-cloud/blog/2024/12/09/sustainable-by-design-next-generation-datacenters-consume-zero-water-for-cooling/) (December 9, 2024) - Meta, [2025 Sustainability Report](https://sustainability.atmeta.com/asset/2025-sustainability-report/) , Water section - State Water Board, [Cross-Connection Control Policy Handbook](https://www.waterboards.ca.gov/drinking%5Fwater/certlic/drinkingwater/cccph.html) : Section 3.3.3 and Appendix D - 22 CCR [Section 60306](https://www.law.cornell.edu/regulations/california/22-CCR-60306) and [Section 60316](https://www.law.cornell.edu/regulations/california/22-CCR-60316) - 40 CFR [141.2](https://www.law.cornell.edu/cfr/text/40/141.2) and [122.26](https://www.law.cornell.edu/cfr/text/40/122.26) - Office of the Governor of California, [Governor Newsom signs data center laws](https://www.gov.ca.gov/2026/09/21/governor-newsom-signs-most-comprehensive-data-center-laws-in-the-nation-providing-communities-more-control-on-water-electricity-and-land-use/) (September 21, 2026) ## How Exodus can help - Related service [Data center water services ](https://www.exoduswater.com/data-center-water-services) - Free tool [Compliance Deadline Checker ](https://www.exoduswater.com/tools#deadline-checker) [Request a Compliance Review](https://www.exoduswater.com/contact-us?service=datacenter) [(805) 991-7333](tel:+18059917333) [Browse all articles](https://www.exoduswater.com/blog) Related service [Data center water services](https://www.exoduswater.com/data-center-water-services)