How Data Centers Use Water
Large data centers generate immense amounts of heat from thousands of processors running around the clock. The primary method for dissipating this heat is evaporative cooling, which works by passing water over cooling towers or through cooling systems where it evaporates, carrying heat away in the process.[1]
This process consumes water - it does not recirculate. Approximately 80% of the water withdrawn by data centers evaporates and is permanently lost from the water system. Most facilities require treated, potable-quality water because reclaimed or recycled water causes more corrosion, mineral scaling, and biological growth in cooling equipment. This means data centers draw directly from the same municipal water supply that serves homes, schools, hospitals, and farms.[2]
The Scale of the Problem
To put these numbers in perspective, consider what 3 million gallons per day means for a community like Pekin:
- The average American household uses about 300 gallons of water per day. Three million gallons equals the daily water use of approximately 10,000 households.[3]
- Pekin's water system serves roughly 32,000 residents. A large data center could significantly increase the demand on that system.
- During summer months, when both residential irrigation and data center cooling demands peak, the strain would be at its worst - precisely when water resources are already under the most pressure.
Why Potable Water Is Required
Data center operators strongly prefer - and usually require - treated drinking water for their cooling systems. Raw or reclaimed water contains minerals, bacteria, and dissolved solids that create scaling, corrosion, and biological fouling in cooling towers. While some newer facilities have experimented with recycled water, the vast majority of operating data centers use municipal potable water.[4]
Pekin's Water Supply
Pekin's drinking water is supplied by Illinois American Water - Pekin District, which draws from 100% groundwater sources. The system operates seven wells at various locations: one drawing from the Sankoty aquifer and six from the Henry formation, with depths ranging from 90 to 154 feet. The system serves approximately 35,000 residents with an average daily supply of 7 million gallons per day.[5]
The Aquifer System
Pekin sits atop significant but vulnerable groundwater resources. The Sankoty Sand Aquifer - one of the most extensive aquifers in Illinois, frequently 100 feet thick - has been used as a water source in the Peoria-Pekin area since 1892. It connects to the broader Mahomet Aquifer system, which provides drinking water to nearly 1 million people across 14 Illinois counties.[6]
Arsenic contamination is already a significant concern in Tazewell County groundwater, with concentrations ranging from 20 to 70 parts per billion - exceeding the EPA standard of 10 ppb. Increased pumping from data center demand could draw contaminated water into currently clean wells and accelerate aquifer drawdown. USGS modeling shows that a hypothetical well field pumping 15 million gallons per day could cause drawdown of 8 to 55 feet, potentially impacting as many as 400 private wells.[7]
Adding a massive industrial consumer to this system raises serious questions:
- Does the groundwater system have the excess capacity to supply millions of additional gallons per day without drawdown?
- Will increased pumping draw arsenic-contaminated water into currently clean well fields?
- Will the data center receive a preferential rate, subsidized by residential ratepayers?
- What happens during drought conditions when aquifer recharge rates decline?
- How will increased demand affect water pressure and quality for existing users?
What Has Happened Elsewhere
The Dalles, Oregon
Google built its first data center in The Dalles (population ~15,000) in 2006, drawn by cheap hydroelectric power. By 2024, Google's facility was consuming 434 million gallons - roughly one-third of the city's total water supply, up from 12% in 2012. When residents and journalists sought water usage records, the city initially denied public records requests, claiming Google's data was a "trade secret." Google even funded the city's lawsuit against The Oregonian newspaper to keep the data private. After litigation, the records were released, and Google announced it would no longer classify site-level water usage as trade secrets.[8]
The city is now seeking to draw water from Mount Hood National Forest to serve Google's growing demand. Residents have taken to calling Google "Voldemort" due to the secrecy surrounding the company's operations.
Newton County, Georgia
Meta's data center in Newton County uses approximately 500,000 gallons of water per day - about 10% of the county's total daily water use. The county is now on track to face a water deficit by 2030 if facilities are not upgraded, with planned water rate increases of 33% over two years (vs. the typical 2% annual increase). Upgrading water infrastructure will cost more than $250 million. Nine additional companies have applied to build data centers in the county, some requesting up to 6 million gallons per day. During Meta's construction phase, residents' water taps ran dry.[9]
Mesa and Chandler, Arizona
In the Phoenix area, data centers have come under scrutiny for water consumption during the worst drought in 1,200 years. Google's Mesa facility was projected to consume up to 4 million gallons of water per day. In Chandler, the city council voted 7-0 to reject a $2 billion data center proposal after receiving more than 250 comments against it. Vice Mayor Jenn Duff stated: "I have very serious concerns about our water in Arizona" during "the driest 12 months in 126 years." Annual water use from data center electricity demand is projected to increase by 400% in the Phoenix region.[10]
What Pekin Should Demand
Before any approvals are granted, the community deserves answers to fundamental questions:
- What is the projected daily and annual water consumption of the proposed facility at full build-out?
- Has a comprehensive water impact study been conducted, including worst-case drought scenarios?
- What water rate will the data center pay, and will it be subsidized below cost?
- What enforceable water conservation measures will be required?
- What happens to resident water access during peak demand or drought conditions?