Smart Engineering Helps Data Centers Manage Water Consumption
For those of us in the water and wastewater industries, data centers are a big deal.
To start, there are a lot of them, with more on the way. Currently, 5426 data centers of all sizes are operating in the United States – and, as of June 2026, more than 1500 additional data centers are in various stages of development and construction. The number will rise as the use of AI grows across every segment of industry.
Those data centers use significant volumes of fresh water to cool their equipment. Together, they consume 449 million gallons (1.7 billion liters) of water per day. That’s 200 billion gallons (757 billion liters) of water per year.
To put that number in perspective, the average American household uses about 300 gallons (1136 liters) per day, or 109,500 gallons (414,503 liters) per year. A small to medium water-cooled data center (about 1 MW) uses about 6000-25,000 gallons (22,712-94,636 liters) of water per day – enough for 20-80 homes – or 219,000-9,125,000 gallons (829,005-34,541,883 liters) per year.
Generally, these monolithic warehouses get their water from four places: surface water; groundwater; municipalities and other managed resources; and “grey” sources like greywater, recycled water, and purified reclaimed water.
“Grey” sources are where the wastewater treatment industry thrives – and they’re great places to find water to cool those data centers.
Reclaiming Manufacturing Water
The use and reuse of greywater from manufacturing and production isn’t a novel concept. In fact, using recycled water or non-potable water for cooling is a well-established practice, particularly in drought-prone areas. Before it’s reused in data centers, however, it requires special treatment to remove minerals and salts.
As water passes through equipment and carries heat away, part of it naturally evaporates, leaving behind dissolved solids that concentrate with each cycle. This concentrated recirculating water – called “blowdown” or “bleed” water – is rich in minerals like calcium, magnesium, and silica. It requires treatment that many plants aren’t equipped to handle.
In Washington, a plant does have the right equipment – thanks to Microsoft.
Since 2007, the company has operated a large data center in Quincy, Washington. It requires millions of gallons of water to cool its high-density cloud computing server farms that sit on its 270-acre (110-hectare) campus. In the past, operations used potable groundwater from the city for cooling the servers. After four to five cooling cycles, they would discharge the blowdown into the sewer system for treatment at the municipality’s wastewater reclamation facility (MWRF).
Unable to handle the mineral- and salt-rich effluent, the City of Quincy and Microsoft partnered to create the Quincy Water Reuse Utility (QWRU), a new facility specifically designed to treat the cooling water from the company’s data center. It took 10 years of planning and construction before it opened in 2021. QWRU is comprised of 10 distinct treatment systems connected by more than 30 miles (48 kilometers) of pipe across Quincy’s industrial area.
The utility is a closed-loop system and does not discharge the blowdown to either the environment or the city’s MWRF. Instead, all the salts are removed from the water prior to its reuse at the data center, concentrated in lined brine ponds, and properly disposed of in a way that prevents their entry into ground or surface waters.
The bottom line: the QWRU substantially reduces the data center’s reliance on potable groundwater for data center cooling, saving an estimated 138 million gallons of water per year (522 million liters per year) through the water reuse treatment system.
Reclaiming Treatment Plant Effluent
The use of treated wastewater effluent to cool machines isn’t a new idea either. As with used water collected from manufacturing, sewer effluent requires extra treatment, too.
In Douglas County, Georgia, for example, Google’s 1.3-million-square-foot data center relies on treated wastewater to cool its servers. Using its own purpose-built system, the Google data center takes effluent from the local water and sewer authority’s treatment plant and treats it even further to make it reusable for server cooling. The extra-treated water is then pumped through the data center’s cooling pipeline.
In addition to using treated effluent, the facility can treat and reuse its own wastewater. It has a National Pollutant Discharge Elimination System permit to allow it to treat its own effluent on-site instead of discharging it to the municipal sewer.
The American Society of Civil Engineers (ASCE) reports the technology has served the cooling needs of the data center for several years and has been used as a prototype for other Google facilities around the world.
Reclaiming Data Center Water
A third option for engineering reclaimed water into data center operations is to reuse blowdown from the facility. Engineers and scientists in Washington, for instance, developed a method for softening blowdown before returning it to the cooling system.
First, minerals like calcium, magnesium, and silica are treated with limewater (calcium hydroxide) to remove hardness due to the salts. The water then flows to an ultrafiltration facility for further refinement via high-efficiency chemical softening (HES) via ion exchange and physical filtration via reverse osmosis (RO). A pipe transfers the HES brine, rich in calcium and magnesium, and the RO brine, rich in silica, to large ponds. There, the water evaporates, leaving behind the residual minerals that are removed and disposed of every two to three years.
The treated industrial wastewater then sits in a permeate tank for about eight hours. The RO and ultrafiltered water are blended at various ratios throughout the day depending on the conductivity levels. Afterward, the treated industrial wastewater is returned to the data center for use as cooling water.
Closing the Loop
As the demand for AI infrastructure accelerates, water reuse will become an increasingly important component of data center design. The facilities highlighted here demonstrate that reclaimed water can reduce dependence on potable supplies while supporting reliable cooling operations.
For utilities, engineers, and treatment providers, the challenge is no longer whether water reuse can work for data centers, but rather how to scale these solutions to meet the demands of a rapidly expanding digital economy.