Budget Amendments Water Rules Weakened by the Governor

Virginia’s new data center water rules are a first step, but they leave a dangerous gap for Prince William County. The budget amendments were intended to protect groundwater and drinking-water supplies from fast-growing data center demand, especially where evaporative cooling can consume large volumes of water during hot, dry periods. Yet Governor Abigail Spanberger’s final language weakened the strongest protections by allowing continued use of evaporative cooling when paired with other efficiency measures, rather than requiring truly water-minimizing systems. The final package also left Prince William out of the Fauquier and Loudoun groundwater management determination, even though all three share the fragile Culpeper Basin fractured-rock system. That distinction matters for the Potomac River watershed, the Occoquan Reservoir, and for Prince William County, where the data center pipeline is now larger and more consequential than Loudoun County’s future buildout.

What the groundwater risks are

Data centers create water risk because many facilities cool servers by evaporating water. Evaporated water is consumed, not returned to the river or aquifer for reuse. During normal conditions this may appear manageable, but during droughts and peak summer heat the same systems can sharply increase demand exactly when water supplies are most stressed. Regional water experts at the ICPRB have warned that data center consumptive use in the Washington metropolitan area could grow from about 8% of total consumptive use in 2025 to 25% by 2035, and that peak-day water demand can rise substantially during hot weather. The risk is not only total annual use; it is the cumulative impact of many large facilities drawing from shared public systems, aquifers, and watersheds at the same time.

• Groundwater depletion: Heavy withdrawals can reduce aquifer levels faster than they recharge, especially in areas already facing long-term groundwater decline or seasonal limits. Increased impervious surfaces reduces recharge.
• Drought vulnerability: Evaporative cooling demand is highest during hot, dry periods, when residents, farms, streams, and public utilities also need reliable water.
• Water-quality concerns: Cooling systems can produce concentrated discharge, the blowdown, that may contain salts, metals, treatment chemicals, or other contaminants that wastewater systems cannot manage.
• Cumulative impacts: A single facility may not appear decisive, but clusters of facilities can overwhelm planning assumptions when many are approved before regional water limits are fully understood.

Why groundwater protection is important

Groundwater protection is essential because aquifers are slow to recover and are a shared public resource. Once groundwater levels decline, the consequences can last for years or decades: drinking-water wells can become less reliable, utilities may face higher treatment and supply costs, streams can lose baseflow, and communities may be forced into expensive infrastructure decisions after the damage is already visible. For Northern Virginia, the issue is especially serious because data centers are concentrated in the Potomac basin, which supplies drinking water to millions of people and supports the Washington metropolitan region. Protection must happen before permitting decisions lock in decades of water demand.

• Prevention is cheaper than correction: It is far less costly to require water-saving cooling systems up front than to retrofit facilities or expand water infrastructure after shortages emerge.
• Water is a public necessity: Drinking water, agriculture, fire protection, streams, and household use should not compete with avoidable industrial consumption during drought.
• Transparency is necessary: Without clear reporting of data center water use, local governments and residents cannot evaluate whether approvals are sustainable.

What the budget amendments tried to do

The original budget language attempted to create Virginia’s first targeted guardrails for data center water consumption. It directed the Department of Environmental Quality to define “Cooling Water Scarcity Areas” by July 1, 2027, where evaporating water for cooling could reduce the quality or quantity of water available for other beneficial uses. In those areas, data centers would have to minimize water use for cooling by relying on air cooling, closed-loop systems, recycled water, stormwater, or similarly efficient technologies to the maximum extent practicable. The budget also created special rules for the Eastern Virginia Groundwater Management Area, requiring new data centers seeking certain air permits after January 1, 2027, to use air cooling, 100% recycled water or stormwater, or a closed-loop system.

In plain terms, the amendments tried to do four things:

First, they tried to identify places where cooling-related water consumption could create scarcity. Second, they tried to move new facilities toward water-saving cooling technologies before new demand became permanent. Third, they tried to protect the most vulnerable groundwater region in eastern Virginia with a clearer baseline standard. Fourth, they began to address the lack of public data by requiring more transparency around data center water sales and use.

How Governor Spanberger weakened the protections

The strongest version of the policy would have pushed data centers away from highly consumptive evaporative cooling in water-stressed areas. Governor Spanberger’s amendment weakened that standard by allowing evaporative cooling to continue if it is used “in conjunction with” other water-efficient methods. That change matters because a hybrid system can still evaporate large amounts of water during the hottest parts of the year. In practice, it lets operators claim efficiency while preserving the very cooling method that creates the greatest consumptive water risk.

The amendment also leaves a timing problem. DEQ does not have to define Cooling Water Scarcity Areas until July 2027, and the broader compliance date extends to 2032. That creates a permitting window in which projects can move forward before scarcity boundaries, enforceable standards, and cumulative water impacts are fully resolved. For communities facing rapid data center growth, delay functions like a loophole.

Why Prince William County faces added risk compared with Loudoun County

Prince William County faces a sharper forward-looking risk because its data center pipeline is expanding while Loudoun County is becoming more constrained. Loudoun remains the global data center hub, with reports describing roughly 200 operating data centers and a large existing footprint. But Loudoun has tightened zoning and has fewer suitable parcels left for by-right development. By contrast, Prince William has positioned large areas for data center growth and has major projects already approved, under construction, or proposed.

This omission is especially serious because the Culpeper Basin is a fractured-rock basin, not a broad, layered coastal plain aquifer like the Potomac system. In the Potomac aquifer, water is stored and moves through more continuous sediment layers; in the Culpeper Basin, water availability depends on irregular fractures in hard rock. That makes supply more localized, less productive, harder to model, and more vulnerable to well interference. Pumping from one high-capacity well can lower water levels in nearby fractures, reduce yields in neighboring wells, or intercept groundwater that would otherwise discharge to streams as baseflow. More future buildout pressure: Prince William has been reported to have at least 44 existing data center buildings totaling about 8.3 million square feet, with enough approved, under-construction, or otherwise active projects to potentially exceed 80 million square feet. That would surpass Loudoun’s projected buildout ceiling of about 40 million square feet in the next decade.

• More pipeline uncertainty: Other regional reporting has described Prince William as having dozens of planned data centers, including about 23 million square feet across roughly 1,500 acres, while Loudoun already has a mature base and a more restrictive approval environment.
• Left out of the Fauquier/Loudoun groundwater review: Prince William was omitted from the budget language directing DEQ to evaluate whether western Loudoun and Fauquier need a Groundwater Management Area, even though western Prince William lies in the same fragile Culpeper Basin fractured-rock system. That omission treats groundwater as if it stopped at county lines, when fractured-rock aquifers move through connected cracks, faults, joints, and weathered zones across the basin.
•  Unmonitored and unmanaged withdrawals: Because Prince William was left out, large data centers could rely on groundwater without the same basin-wide monitoring, withdrawal accounting, or management review being considered for Loudoun and Fauquier. In a fractured-rock basin that is far less productive and less predictable than the layered Potomac aquifer, that creates direct risk for private wells, community wells, and the groundwater-fed baseflow that sustains streams and rivers feeding the Occoquan Reservoir.
• Potomac watershed exposure: Rapid growth in Prince William would add demand in the Potomac basin, where regional studies already identify data center water use as a growing concern during drought and peak summer demand.

The bottom line

The budget amendments recognized the right problem: data centers can place serious cumulative stress on groundwater, public water systems, and the Potomac watershed, especially when evaporative cooling expands during drought and heat. But the final language does not go far enough. By permitting hybrid evaporative cooling, delaying enforceable scarcity designations, and leaving Prince William out of the Fauquier/Loudoun groundwater management determination, Governor Spanberger’s amendments weakened the standard at the moment Virginia needed a clear statewide rule. Prince William County is especially exposed because it has a larger future pipeline than Loudoun County, sits in the same fragile Culpeper Basin fractured-rock system, and could allow data centers to draw unmonitored and unmanaged groundwater that endangers private wells, community wells, and the baseflow of streams and rivers feeding the Occoquan Reservoir.