Contextualizing Data Center Water Use
A 40 MW data center in Phoenix requires about 1.8 million gallons of water per year (~5.7 acre-feet) for adiabatic precooling to ensure the entering air temperature at the air-cooled chiller condenser inlet does not exceed 110°F. Sometimes referred to as peak trimming or peak shaving, the adiabatic precooling process involves evaporating a small amount of water to pre-cool the entering airstream during periods of high temperature.
So how does data center water usage stack up against other water-intensive industries in Arizona?
⛳ Arizona’s Golf Courses: Verdant But Thirsty
- Total usage: ~119,478 acre-feet annually across 219 courses (~39 billion gallons)
- Per course average: ~504 acre-feet (~164 million gallons) per year
- Context: Our data center scenario uses ~1% of a single golf course.
🌾 Agriculture: The State’s Primary Consumer
Above: A center-pivot irrigation system in Arizona.
- Statewide agriculture uses 70–74% of Arizona’s water usgs.gov
Alfalfa Farming Example
- Total alfalfa farm usage: ~1.3 million acre-feet annually across 260,000 acres (~423 billion gallons per year)
- Per alfalfa field average: The average field is 300 acres and uses ~1,500 acre-feet of water per year (488 million gallons per year)
- Context: Our data center scenario uses 0.34% of a single alfalfa field.
🏭 Other High-Volume Water Users
- Niagara Bottling (Mesa): Holds permits for ~40 million gallons per year —roughly 22× more than our data center case.
- Aquaculture farms: likely consume tens of millions annually—10–50× the data center's use
- TSMC: TSMC's first Arizona chip fab facility is projected to use 4.7 million gallons of water per day initially, but the company expects to reduce this to 1 million gallons per day through water recycling. When fully built out, including all three planned fabs, TSMC estimates a combined water demand of 16.4 million gallons per day. However, with planned water recycling, the net water usage is expected to be significantly lower.
🔍 Quick Comparison Table
Why use any water at data centers?
We are strong proponents of water conservation and strenuously oppose the use of evaporative technologies as the primary means of cooling a data center. However, water has an important role to play in the context of all economic and environmental tradeoffs facing the data center industry and society generally. The amount of water used for power generation in the table above is an example of this. When used for peak shaving, a relatively small amount of water for adiabatic precooling will:
- Safeguard site reliability during periods of high ambient temperature.
- Reduce the seasonal underutilization of power generation resources and other capital investments.
Now is the time for the data center industry to be less dogmatic and more pragmatic about water sustainability. Peak shaving using adiabatic precooling is both pragmatic and sustainable.
Why is Data Center Water Usage Heavily Scrutinized?
Ten years ago, many large data centers used cooling towers or direct evaporative walls as the primary means of heat rejection. These technologies are energy efficient but water intensive. In the last five years or so, heightened concerns about water sustainability have moved the industry toward air-cooled chillers as the primary means of heat rejection. The rapid shift is easy to explain. The data center industry is driven by some of the largest, wealthiest, tech companies in the world. The so-called “hyperscalers” Amazon, Microsoft, Google, Meta, Apple, and Oracle are all headquartered in California and Washington, on the west coast of the United States. These tech behemoths became lightning rods for public ire during recent California droughts and the ongoing pressure on Colorado River water resources. To their credit, the commitments that these companies made to water sustainability influenced a rapid turnaround in the data center industry’s approach to water use.
Suggested Solution
The most obvious and effective mechanism to protect water resources for future generations may simply be the market mechanism. Charging higher rates for water would provide a natural incentive for large, industrial-scale users to consume less water. Pricing increases could be applied to commercial customers only, or universally. Sliding scale pricing would insulate lower income households from marginal price increases because those households tend not to have swimming pools or extravagant landscaping that drive high water consumption.
