How Data Centers Use Water

Data centers require large amounts of water primarily for cooling. Modern facilities use evaporative cooling towers that remove heat by evaporating water — the same principle as sweating. In hot, dry climates like Central Texas, these towers are especially water-intensive because higher ambient temperatures demand more evaporation to achieve the same cooling effect.

Cooling tower basics

A cooling tower works by circulating hot water from server room heat exchangers over a fill media, where air flow causes evaporation. The cooled water returns to the servers; the evaporated water is lost to the atmosphere and cannot be recovered.

Typical data center water use metrics:

• WUE (Water Usage Effectiveness): liters of water consumed per kWh of IT equipment energy. Industry average is approximately 1.8 L/kWh; best-in-class facilities reach 0.2 L/kWh using air or seawater cooling.
• PUE (Power Usage Effectiveness): total facility power divided by IT equipment power. A PUE of 1.0 is perfect; typical is 1.2–1.6.

Why Texas is different

The Edwards Aquifer recharge zone — where several proposed Hays County facilities are sited — overlies the primary water source for approximately 2 million Central Texans. Unlike Northern Virginia (the largest U.S. data center market), Texas cannot rely on winter-season air cooling to offset summer water demand. During the hottest months — when Stage 3 drought restrictions are most acute — data center water consumption peaks.

The hidden number: water for power generation

WUE and direct cooling figures only tell half the story. Power plants also use water — and that water use is almost never included in data center water impact assessments.

Generating electricity from natural gas (the dominant fuel in Texas) requires water to cool turbines and condensers. A combined-cycle gas plant uses approximately 0.3–0.5 gallons of water per kilowatt-hour generated. A steam-cycle plant uses 0.4–0.8 gallons per kWh. At the scale of a 1 GW data center running continuously:

• 1 GW × 24 hours × 0.3 gal/kWh = ~7.2 million gallons per day (low estimate, combined-cycle)
• 1 GW × 24 hours × 0.5 gal/kWh = ~12 million gallons per day (high estimate)

When a data center draws from the regional grid (ERCOT), this power-generation water use is spread across many plants in many locations — some distant from the aquifer. But when a developer builds an on-site gas plant — as CloudBurst Data Centers has done at its 2955 Francis Harris Lane campus with an Energy Transfer pipeline supplying up to 450,000 MMBtu per day of natural gas — the power-generation water is consumed entirely locally, drawing from the same Crystal Clear Special Utility District that serves nearby residents.

In practice this means the total local water impact of a large on-site-powered data center campus may be 2–5× higher than the direct cooling figure alone. The Central Texas Data Center Tracker's project database reports both numbers where available.

Texas data center water use — current scale

Texas data centers are projected to use approximately 49 billion gallons of water in 2025, according to a 2024 analysis by the Houston Advanced Research Center (HARC). At full buildout of all proposed facilities, annual water consumption could reach 29–161 billion gallons by 2030 — up to 2.7% of the state's total water use.^[1]

A 2021 study in Environmental Research Letters estimated a single 15 MW data center using evaporative cooling in a hot climate consumes approximately 130 million gallons per year.^[2] At 360–1,200 MW — the range of proposed facilities in Central Texas — a large campus can evaporate 3–16 million gallons per day.

---

Sources

1. ^ Houston Advanced Research Center (HARC), "Texas Data Center Boom Could Consume Up to 161 Billion Gallons of Water Annually by 2030," 2024. Available at harcresearch.org.
2. ^ Siddik, M.A., Shehabi, A., & Marston, L., "The environmental footprint of data centers in the United States," Environmental Research Letters, Vol. 16, No. 6, 2021.