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  "title": "Water withdrawal, consumption and cooling circulation",
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  "description": "Accounts for local water effects with a defined physical and energy denominator.",
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  "publishedDate": null,
  "revisionDate": "2026-10-07",
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  "topic": "Global AI infrastructure",
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      "id": "section-1",
      "title": "Water withdrawal, consumption and cooling circulation",
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      "title": "Consumption-based WUE",
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      "title": "Which quantity belongs in a site consumption-per-IT-energy ratio?",
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    {
      "title": "Explore in Atlas",
      "url": "https://semiaifoundry.com/ai-atlas/#water-boundary-accounting"
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    {
      "title": "Cooling Water Efficiency Opportunities for Federal Data Centers",
      "url": "https://www.energy.gov/cmei/femp/cooling-water-efficiency-opportunities-federal-data-centers"
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      "url": "https://semiaifoundry.com/learn/atlas/coolant-loop-separation/"
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    {
      "title": "Facility heat rejection and cooling tradeoffs",
      "url": "https://semiaifoundry.com/learn/atlas/facility-heat-rejection/"
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  "content": "Global AI infrastructure · Atlas v1.3.0\n\n# Water withdrawal, consumption and cooling circulation\n\nAccounts for local water effects with a defined physical and energy denominator.\n\n[Explore in Atlas](https://semiaifoundry.com/ai-atlas/#water-boundary-accounting)Facility phases to region and world; geography schematic\n\nLearning objectiveDistinguish physical water flows and calculate a correctly scoped WUE.\n\n## The mechanism\n\nCooling water can circulate repeatedly, be withdrawn from a source and returned, or be consumed through evaporation and other losses. These are different quantities. Site water usage effectiveness divides an explicitly defined water amount by IT energy over the same interval, while electricity generation can create additional off-site water impacts. The Department of Energy explains water-efficiency measures and cooling-system tradeoffs. Annual averages can conceal seasonal stress and local basin conditions. A replenishment or matching claim is also distinct from water being physically available at the same place and time when a cooling system needs it.\n\n1.  Draw the water-system boundary and distinguish closed-loop circulation from external makeup.\n2.  Measure withdrawal and return flows to identify the consumed amount under the chosen definition.\n3.  Match water and IT-energy intervals when calculating site WUE.\n4.  Account for electricity-related water separately using a documented regional method.\n5.  Inspect seasonal and basin conditions instead of treating one annual ratio as a complete impact measure.\n\n## Science and assumptions\n\n### Consumption-based WUE\n\n$$\n\\mathrm{WUE}=\\frac{V_{\\mathrm{consumed}}}{E_{IT}}\n$$\n\nConsumption-based WUE is liters of water consumed divided by IT kilowatt-hours over the same interval.\n\nSymbols and units\n\nWUE\n\nConsumption-based water-use effectiveness for the chosen scope\n\nL/kWh\n\nV\\_consumed\n\nWater consumed within that stated scope and interval\n\nL\n\nE\\_IT\n\nIT energy over the same interval\n\nkWh\n\nVconsumed is liters and EIT kWh, giving L/kWh.\n\nAssumptions This explicitly selected definition must match the source; some reporting frameworks use different water scopes.\n\n## Engineering example\n\nSynthetic 10 MW IT load running 24 hours uses 240,000 kWh. At an explicitly assumed 0.2 L/kWh consumption ratio, the corresponding consumption is 48,000 L/day, independent of the much larger circulating flow.\n\n## Distinctions and tradeoffs\n\nA large closed-loop flow rate does not mean that amount of water is consumed, and low site water use does not prove zero indirect water impact.\n\nReducing direct water consumption can increase electricity demand under some cooling choices; local basin conditions determine the significance of either tradeoff.\n\nHigh-density computing needs thermal service, but chip efficiency alone does not establish a site’s water impact.\n\n## Specifications and interfaces\n\nWater categories\n\nWithdrawal, return, consumption and circulation\n\nVolumes require a stated boundary and interval.\n\nWUE denominator\n\nLiters per IT kWh when defined that way\n\nDo not silently substitute facility kWh or coolant L/min.\n\n### Interfaces\n\nSource water and cooling operation Input\n\nMakeup flow, evaporation, discharge and supply conditions\n\nWater ledger Output\n\nConsumed and returned volumes with local context\n\n## Check your understanding\n\n### Which quantity belongs in a site consumption-per-IT-energy ratio?\n\n1.  Consumed liters and IT kWh over the same interval\n2.  Circulating liters/minute divided by chip count\n3.  Only the annual rainfall total\n\nAnswer and reasoning\n\nConsumed liters and IT kWh over the same interval\n\nA meaningful ratio requires compatible consumption and energy boundaries over an aligned period.\n\n## Evidence and scope\n\nThe WUE value is synthetic. No operator’s water performance, basin availability or regulatory compliance is inferred from this calculation.\n\nBrowse the numerical library; no current calculator directly models this lesson’s central mechanism.\n\n## Sources\n\n-   [Cooling Water Efficiency Opportunities for Federal Data Centers](https://www.energy.gov/cmei/femp/cooling-water-efficiency-opportunities-federal-data-centers)\n\n[Published lesson data](https://semiaifoundry.com/ai-atlas/lesson-data/water-boundary-accounting-86ed10c29df2e1b0.json) · [Atlas releases and licensing](https://semiaifoundry.com/ai-atlas/licenses.html)\n\n## Continue exploring\n\n### Foundations\n\n-   [Cold plates, manifolds and separated coolant loops](https://semiaifoundry.com/learn/atlas/coolant-loop-separation/)\n\n### Related lessons\n\n-   [Facility heat rejection and cooling tradeoffs](https://semiaifoundry.com/learn/atlas/facility-heat-rejection/)\n-   [Energy forecasts, geography and measurement boundaries](https://semiaifoundry.com/learn/atlas/energy-forecast-boundaries/)"
}