Dateline Ashburn: The Thirst for AI Raises Alarms in Virginia
Drought and water restrictions have already hit 'data center alley,' but closed loop systems used by 2/3 of Ashburn data centers promise relief.
ASHBURN, Va., Sept. 12, 2025 – Already strained by drought and restrictions, Virginia’s “data center alley” watches as the rise of artificial intelligence accelerates demand for fresh, potable water.
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Despite the seemingly abundant water supply in Ashburn, Virginia – home to the world’s largest cluster of data centers – the region has already begun to experience the reality of climate change and water scarcity. In 2024, Loudoun County faced a months-long drought that triggered mandatory water use restrictions across the area.
As digital infrastructure carrying global internet traffic and AI workloads expands in the region, feeding it was straining not only the region’s security, bandwidth, and electric grid, but also its most basic resource: Water.
Data center water consumption in 2023 hit about 900 million gallons for Loudoun County alone, and nearly 2 billion gallons across Northern Virginia. That was a 63 percent increase from 2019 levels.
In 2025, large data centers were consuming up to 5 million gallons of water per day, equivalent to the water use of a town populated by 10,000 to 50,000 people, according to the Environmental and Energy Study Institute.
Water is primarily used as a liquid coolant, circulated through pipes and heat exchangers to dissipate the heat generated by the servers and other data center equipment. Most data centers utilize potable water from local water utilities as their main source for cooling due to its refined quality, reducing the risk of corrosion, scaling, and microbiological growth in the equipment.
Of the Earth’s water, only about 0.5 percent is both accessible and safe for human use – a supply that data centers are now competing to tap.
Water works in the data center capital of the world
Ashburn, Virginia, located in the heart of “data center alley,” is home to at least 199 data centers, with more on the way. One of the factors that made the location so appealing was its close proximity to the Potomac River, providing a steady flow of water for cooling systems that can easily be accessed through municipal water suppliers.
“Some of these data centers will use resources equivalent to a small city for energy and water,” Ann Bennett, chair of data center issues in the Sierra Club’s Virginia chapter, told Grist. “They are being built on a scale that we just haven’t seen in the past.”
However, pinpointing the exact amount of water, and what type, currently being used has proven difficult due to a lack of publicly available data. According to a 2021 survey, only 10 percent of data center operators monitor and record water usage across their facilities.
Many data centers in Ashburn obtain their water from Loudoun Water, the county’s local water authority. While Loudoun Water has worked to utilize reclaimed water to cool these data centers, the rapid surge in demand for water has led to continued use of freshwater resources in some facilities.
Some relief from reclaimed water
Loudoun Water constructed its first pipelines for a reclaimed water distribution system in 2010 for industrial cooling in Ashburn’s emerging data centers. The reclaimed water distribution system now contains 20 miles of pipeline, delivering 736 million gallons of reclaimed water to data center customers in 2024.
This effort is “helping to save an equal amount of precious potable drinking water while reducing nutrients discharged to the Potomac River and Chesapeake Bay,” according to Loudoun Water’s website.
Mike Beardslee, executive director of technology services for Loudoun Water, claimed that both parties are benefiting from this system.
“The data centers get the cooling water they need at a reduced rate, and we’re getting paid for reclaimed water that would otherwise be discharged into a stream,” Beardslee told Water Environment & Technology..
Open vs. closed loop systems
In addition to the type of water being used, different systems employed for cooling have different environmental impacts. Closed loop systems, utilized by roughly two-thirds of the data centers in Ashburn, are much more environmentally friendly than their open loop counterparts.
In open loop systems, the water used for cooling is pumped into a cooling tank, where it comes into direct contact with the outside air to lower its temperature naturally. This method is appealing in areas with a strained power grid as it requires minimal energy use, but is extremely water intensive as much of the water used for cooling evaporates.
Conversely, closed loop systems enable the reuse of both recycled water and freshwater, reducing the need for constant replenishment. Cooling is achieved in a tower through external air being brought in, allowing the water to return to its original temperature, or by a refrigerant.
The World Economic Forum reported that the transition from an open to closed loop system can reduce freshwater use by up to 70 percent.
Facing the reality of water demand in Loudoun
Despite the fact that some of Ashburn’s data centers are utilizing recycled water, and more than half of them employ a closed loop system, community and environmental groups have raised a number of real concerns.
The Piedmont Environmental Council warned that as more data centers are built, impervious cover – or hard surfaces that prevent the infiltration of water into the ground – increases, reducing the land’s natural ability to absorb rainfall, resulting in more stormwater runoff.
Not only does this increase the likelihood and severity of floods, but it draws more pollutants into drinking water, harms aquatic ecosystems, and erodes stream banks.
Alimatou Seck, a scientist at the Interstate Commission on the Potomac River Basin, worked with water suppliers in Loudoun County to demonstrate the increasing strain that data centers are putting on local water resources.
Seck found that “data center alley” currently consumes about 2 percent of the water used from the Potomac River Basin, a figure that increases to 8 percent in the summer when hotter temperatures require more water for cooling.
She predicts that data center growth at its current pace using standard cooling technologies could drive this figure upwards of 33 percent by 2050, requiring 200 million gallons of Potomac water per day.
“As we look towards climate change and drought, somebody has to start asking these questions about how that impacts water supply and future increasing need,” Kyle Hart, program manager of the National Parks Conservation Association in Alexandria, told Grist.
Legislative efforts stalled in Richmond
In both 2024 and 2025, dozens of bills targeting oversight of data-center environmental or water use impacts were proposed in Virginia. But in each year, nearly all failed – either in committee, during crossover, or via veto.
For example, in 2025, at least four major bills advancing protections around water, land use, or power infrastructure – HB 2101, HB 2027, HB 2578, HB 2035 – did not pass. Only one key oversight measure, HB 1601, made it through the legislature, and it was ultimately vetoed.
The measure, introduced by Delegate Josh Thomas, D-Prince William, would have required data center developers to conduct impact assessments on ground and surface water resources, as well as agricultural resources, parks, registered historic sites, and forestland.
The legislation cleared both chambers of the General Assembly but was vetoed by Governor Glenn Youngkin (R) who in May dismissed the measure as an unnecessary burden.
“This bill limits local discretion and creates unnecessary red tape,” Youngkin said in a statement, noting that data centers support about 74,000 jobs, $5.5 billion in labor income, and $9.1 billion to GDP annually.
That lack of progress, some observers argue, stems from a deeper problem.
“I think it’s very fair to paint a picture of a very obstinate industry that is opposed to any type of check on its growth,” Thomas told Grist. “If we don’t do something quickly, there may be a tipping point where anything we do might not have an impact.”
According to Julie Bolthouse, director of land use at the Piedmont Environmental Council, this can be attributed both to a lack of data on how much water data centers are actually consuming, coupled with the fact that the county boards of supervisors who approve data centers stand to see significant tax revenue increases from doing so.
“We just don’t know. And that’s the biggest problem: We need more transparency around this industry,” Bolthouse told Grist. “And yet we’re approving them because of the promise of increased revenue.”
First Dateline Ashburn story: How to Break the Internet
Second Dateline Ashburn story: How do IXPs contribute to infrastructure resiliency?
Third Dateline Ashburn story: What is the energy impact of data centers?
Fourth Dateline Ashburn story: What is the water impact of data centers?
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