HARRISONBURG, Va. – Data centers are not just a Northern Virginia problem. The vast and growing presence of these warehouse-like buildings housing the world’s computing power has implications for quality of life, land, energy and water across the Chesapeake Bay region.
This was the main message of a half-day workshop on May 19 hosted by the Choose Clean Water Coalition at the start of its annual conference held this year in Harrisonburg, VA. The “kickoff” event featured experts mostly from Virginia speaking about the environmental impacts of data centers, which they have seen firsthand — and which they say are imminent for every state in the region.
Northern Virginia is the global epicenter of data center infrastructure and home to about half of all data centers in the U.S. This distinction is not new but has garnered increasing attention as the global race to power artificial intelligence begins to strain regional power supplies. Researchers at the workshop warned that continued unrestrained growth of data centers in the Potomac River basin in the coming years could strain the region’s water supply as well.
Lydia Lawrence, the director of conservation for the nonprofit Nature Forward, said she has been urging the broader clean water community to discuss the implications of data centers for some time now. That’s in large part because she lives in Herndon, VA, where she’s watched data centers replace forests near her home and then seen the trail she runs lined by larger and larger transmission lines.
Earlier this year, she told workshop participants, Nature Forward held a webinar on the health implications of living near data centers.
“We got people from 30 states that came,” she said, “because data centers are impacting all of us … including every state in the Chesapeake Bay watershed.”
Data centers — and the solar panels, transmission lines and other energy improvement projects necessary to run them — are contributing to some of the largest land use changes in many parts of the region.
Julie Bolthouse, land use director for the Piedmont Environmental Council, is closely following data center growth in Virginia. She said Loudoun County is now home to more than 40 million square feet of them — enough to completely cover New York City’s Central Park. And Prince William County, she said, “is racing, trying to catch up.”
“We are at about 60 million square feet of data centers in Virginia, and we have more than 200 million square feet in the pipeline,” she said, referring to additional data centers that have been approved but not yet built.
Del. Josh Thomas (D-Prince William County) said that while Loudoun County officials have said they are nearing a saturation point for data center construction, Prince William County leaders still have large projects on the drawing board that, if all constructed, would bring the county’s total to around 80 million square feet.
“That’s 80 million square feet of concrete that will create that much more runoff that will go into the Occoquan Reservoir,” he said, referring to one of two major sources of drinking water for residents of Prince William and Fairfax counties (the other is the Potomac River). “And then all that’s going to flow into part of the region we are here for today, which is the Chesapeake Bay.”
During a panel discussion, Thomas and others who have opposed specific projects or worked to get data center legislation passed in Virginia explained why it’s been so hard to do so. Many data center projects are approved on a case-by-case basis by county boards of supervisors — who also stand to see significant tax revenue increases from approving them.
Advocates formed the Virginia Data Center Reform Coalition in early 2024 to promote a flurry of state bills aimed at reining in the industry’s environmental and economic impacts. But, of the 30 bills proposed during the 2025 session, onlyone made it through both chambers and avoided the governor’s veto this year.
Data center development, and the transmission lines and energy production necessary to fuel it, is already up for heated discussion in other Chesapeake Bay states, too.
Maryland Gov. Wes Moore, a Democrat, told his state legislators in May that he intended to veto a bill that aimed to study the economic, environmental and energy consequences of data center development in the state. He said financial constraints and uncertainty about federal funding contributed to the decision.
Two companies are currently working together to develop a 2,100-acre data center campus known as Quantum Frederick in Maryland. The campus would be connected to Loudoun’s so-called data center alley to the south by a 40-mile “loop” of fiber-optic cable, expanding data center capacity to future occupants.
Nature Forward’s Lawrence said her Maryland-based nonprofit is currently working to create a data center reform group similar to the one in Virginia.
“I would urge every other state to consider setting up something similar,” she said.
States not experiencing an influx of data center development will still be impacted by the additional infrastructure needed to create and carry massive amounts of energy throughout the region to data centers.
Demand for electricity from data centers in Virginia alone nearly doubled in the second half of 2024, rising to consume about 40 gigawatts of power by the end of that year, according to Dominion Energy (enough to power approximately 10 million homes). The AI boom’s increasingly complex models also pack vastly more energy- and cooling-intensive computing into every square foot of the even larger data centers currently under construction.
Major questions remain about the industry’s long-term impacts, particularly on the quality and quantity of local water supplies.
Alimatou Seck, a senior water resources scientist at the Interstate Commission on the Potomac River Basin, presented at the workshop her recent calculations of data center water use. Since the water use of individual centers is typically not made public, Seck worked with water suppliers in the region to calculate averages and cumulative uses in the region (information that environmental advocates have been seeking for some time).
Data centers use water to cool the computer servers most commonly through either evaporative cooling, which uses water to absorb heat and then evaporate, or air cooling (essentially air conditioning). The latter requires more electric power but less water. Synthetic liquid cooling is also used at some specialized data centers. Some Loudoun County data centers use reclaimed water for cooling purposes.
But water use has been going up alongside energy use as the facilities expand both their scale and intensity in the region. And the epicenter of that water use is concentrated in the Potomac River basin, where water supplies have been sufficient so far but are subject to droughts and other stressors.
Seck of the Potomac commission found that data centers currently consume about 2% of the water used from the river basin. But that number shoots up to 8% during the summer months. If the industry continues to grow at an unconstrained pace using standard cooling technologies, she projected that number could surpass 33% by 2050, requiring 200 million gallons of Potomac water per day. For context, the greater Washington, DC, area currently uses a maximum of about 600 million gallons per day from the Potomac at the peak of water use in August.
“We don’t know what will happen with energy or regulatory pressure, but it’s an issue we will have to follow closely in the future,” said Seck, whose initial findings are still under review and being circulated among stakeholders for feedback.
She pointed out that the numbers do not include water use for power-generating plants, which can be an additional large category of growth related to the industry.
After absorbing information from panelists, the Choose Clean Water workshop attendees split into groups to discuss their roles when it comes to data centers. Some focused on energy or water use while others considered the need for better communication strategies.
“It’s not in the cloud. It is very physical on our land,” Rosa Hance, an energy policy contractor with Choose Clean Water, said to summarize her takeaways from the event. “We are seeing how massive it is, and it’s up to us to do something about it.”