Brief · Water honesty kit
Data-center water: what to demand, what not to invent
Data centers use water mainly to stay cool, and more is used at the power plants that supply them. Nobody publishes a trustworthy per-campus water number, so don’t repeat one without the site’s own filing. The only national water figures we can verify are modeled estimates: U.S. data centers consumed about 66 billion liters of water on site in 2023, and about 800 billion liters more indirectly through power generation (LBNL, 2024). No public federal source gives a reliable per-campus number. Any “X gallons per day” claim for a specific site has to come from that site’s own dated utility, permit, or engineering filing, or it is unknown.
Why it matters: if a data center is proposed near you, ask for that site’s own water filing. National estimates cannot tell you what one campus will use, and we do not invent campus gallons or job counts.
What DataCenterSkilledTrades says this means
- Contractors (GC / trade contractors): Don’t put water numbers in a bid that aren’t in the owner’s basis of design. Speak to scope: pipefitters on CDU and facility water loops, HVAC/R on chillers and towers (liquid cooling guide, roles).
- Hiring ops: Water-loop and cooling-tower work is trade scope: hire against the system on facility systems, not against a water headline.
- Local gov / HOAs: Ask for a dated, sourced figure split into consumed vs withdrawn, average vs peak, with the cooling design named. If the proposer can’t answer, record the number as unknown.
Tiny glossary
- Withdrawn
- Water taken from a source; part may return (discharge).
- Consumed
- Water permanently removed from the local cycle, mostly by evaporation (LBNL’s definition).
- Site WUE
- Water Usage Effectiveness: liters of on-site water consumed per kWh of IT electricity.
- Indirect water
- Water consumed at power plants generating the site’s electricity, not drawn at the site.
- Once-through vs recirculating
- Once-through passes water through and discharges it; recirculating (e.g., cooling towers) reuses it and loses some to evaporation and blowdown.
For local governments & HOAs: demand these in every proposal
- A named, dated source for every water number (utility will-serve letter, permit application, or engineer’s basis of design), not a press release.
- Consumptive vs withdrawn, stated separately.
- Average day and peak day, and which one the headline number is.
- Cooling design: evaporative cooling towers, air-cooled or water-cooled chillers, adiabatic assist, closed-loop direct-to-chip liquid cooling, and what rejects the heat.
- Once-through vs recirculating, cycles of concentration, and where blowdown/discharge goes.
- Water source: potable, reclaimed/non-potable, or groundwater, and drought-curtailment or tiered-use plans.
- Build-out phase the number covers (phase 1 vs full campus).
For contractors: don’t pad these into bids
- National LBNL totals presented as your project’s demand.
- Viral “X gallons per day” figures, or another campus’s numbers.
- “Liquid cooling = zero water” claims; heat rejection still sets site water.
- Any gallons not in the owner’s basis of design or a utility filing. If it isn’t sourced, write “per owner’s engineering basis” and leave the number out.
Scope you can speak to: facility water and CDU loops (pipefitters), chillers, towers and refrigerant (HVAC/R with EPA 608). See facility systems · liquid cooling and liquid cooling guide.
What is known nationally, and what is not
- Known (modeled): 66 billion liters direct consumption (2023), 21.2 billion (2014), 60–124 billion liters projected for hyperscale alone in 2028, site WUE just over 0.36 L/kWh through 2023, indirect ~800 billion liters (2023). All LBNL 2024.
- Unknown from federal sources: water use for any specific campus, county, or utility service area; peak-day demand; per-job or per-MW water. DataCenterSkilledTrades publishes none of these.
- Liquid cooling: LBNL notes average WUE rising after 2023 partly from liquid-cooled systems. Closed loops don’t remove the heat-rejection question.
Citable figures (DataCenterSkilledTrades Dataset)
Every row: value, date, primary source, retrieval date. Units kept as published (liters for LBNL; gallons only where USGS published gallons).
| Metric | Value | Context | Date & source |
|---|---|---|---|
| U.S. data-center direct (on-site) water consumption, 2023 Modeled national estimate (consumption, not withdrawal). Not a per-campus number. | 66 billion liters | Hyperscale + colocation = 84% of the total; internal (enterprise) data centers 12% | 2023 (report Dec 2024) LBNL 2024 United States Data Center Energy Usage Report (Shehabi et al., Dec 2024, LBNL-2001637), §5, p. 55 · retrieved 2026-11-05 |
| U.S. data-center direct water consumption, 2014 | 21.2 billion liters | 64% in internal data centers that year | 2014 LBNL 2024 United States Data Center Energy Usage Report (Shehabi et al., Dec 2024, LBNL-2001637), p. 55 · retrieved 2026-11-05 |
| Projected hyperscale direct water consumption, 2028 Quote the range, never the top end alone. | 60–124 billion liters | Scenario range: a projection, not a measurement | 2028 (projection) LBNL 2024 United States Data Center Energy Usage Report (Shehabi et al., Dec 2024, LBNL-2001637), pp. 55–56 · retrieved 2026-11-05 |
| Average site WUE, all U.S. data centers Rise reflects hyperscale/colo mix and liquid-cooled systems in LBNL’s model. | just over 0.36 L/kWh through 2023; 0.45–0.48 L/kWh after 2023 | Liters of on-site water consumed per kWh of IT electricity | 2014–2028 (modeled) LBNL 2024 United States Data Center Energy Usage Report (Shehabi et al., Dec 2024, LBNL-2001637), p. 48 · retrieved 2026-11-05 |
| U.S. data-center indirect water footprint (via electricity generation), 2023 Water consumed at power plants, not at the data-center site. Do not add it to an on-site permit request. | nearly 800 billion liters | National average 4.52 L/kWh for data-center electricity vs 4.35 L/kWh U.S. overall | 2023 LBNL 2024 United States Data Center Energy Usage Report (Shehabi et al., Dec 2024, LBNL-2001637), p. 57 · retrieved 2026-11-05 |
| Total U.S. water withdrawals, all uses (context only) National withdrawals across all sectors. Not a data-center number; it is shown so readers keep withdrawn vs consumed straight. | about 322 billion gallons per day | Freshwater 281 Bgal/d (87%); withdrawals, not consumption | 2015 (USGS Circular 1441, published 2018) USGS Circular 1441, Estimated Use of Water in the United States in 2015 (Dieter et al.) · retrieved 2026-11-05 |
Compiled table licensed CC BY 4.0.
FAQ
How much water do U.S. data centers use?
On LBNL’s national model (2024 report, Shehabi et al.): about 66 billion liters of direct, on-site water consumption in 2023, up from 21.2 billion liters in 2014. Indirect water consumed at power plants to make their electricity was nearly 800 billion liters in 2023. Those are national modeled estimates of consumption, not a figure for any single campus.
Is the viral ‘X gallons per day’ number for a data center true?
Maybe, for one site, if it comes from a dated utility, permit, or operator filing. Many viral figures are site-specific, design-maximum, or unsourced. DataCenterSkilledTrades does not invent campus gallons. Ask for the source document, its year, whether it is consumption or withdrawal, peak or average, and which cooling design it assumes.
What should local governments and HOAs demand in a proposal?
A dated water-use figure tied to a named source (utility will-serve letter, permit application, or engineering basis of design); consumptive vs withdrawn split; average and peak-day demand; cooling design (evaporative towers, air-cooled chillers, adiabatic, closed-loop liquid cooling); water source (potable, reclaimed, groundwater); discharge/blowdown handling; and drought-curtailment plans. If a proposal cannot answer, the number is unknown, so say so.
Does liquid cooling mean zero water?
No. Direct-to-chip liquid cooling moves heat with a closed coolant loop, but that heat still has to be rejected by dry coolers, chillers, or evaporative towers. Site water depends on the heat-rejection side. LBNL’s model shows average site WUE rising after 2023 partly from liquid-cooled systems. Ask what rejects the heat.
What is the difference between withdrawn and consumed water?
Withdrawn water is taken from a source; some returns (e.g., discharged). Consumed water is permanently removed from the immediate water cycle, mostly by evaporation (LBNL’s definition). A once-through system can withdraw a lot but consume little; an evaporative tower consumes much of what it uses. Never compare a withdrawal number to a consumption number.
What should contractors not pad into bids?
Do not quote national LBNL totals, viral per-day gallons, or another campus’s figures as your project’s water use. Water numbers in a bid or community presentation should come from the owner’s engineering basis of design or utility filings. Contractors can speak to scope: pipefitters on CDU and facility water loops, HVAC/R on chillers and towers, not invent demand.
Is the USGS 322 billion gallons per day figure about data centers?
No. USGS Circular 1441 estimates about 322 billion gallons per day of total U.S. water withdrawals in 2015 across all uses. It is context for scale and for the withdrawal-vs-consumption distinction only.