Northern Virginia’s wary embrace of data centers could have major long-term impacts on both water consumption and wastewater treatment across the region, the Fairfax County Environmental Quality Advisory Council (EQAC) says in its annual report for 2024.
The 134-page document offers a status update and recommendations on environmental issues, including land use, air and water quality, transportation, waste management, climate change and ecological conservation.
A section on water supply and wastewater treatment, and how data centers could impact both, might raise eyebrows the highest among regional policymakers.
Data centers require large amounts of electricity to operate, and one option for addressing all the heat that’s produced as a byproduct is evaporative cooling, a ventilation system that utilizes water to cool the air.
In one scenario suggested in EQAC’s report, a major uptake of evaportive cooling by large new data centers in the region could require 70 million gallons of water per day — “almost doubling” the existing consumptive water use in the Potomac River basin.
Agencies that handle the D.C. region’s water flow would face the burden of making more water available at the outset and treating the residual amount that flows into wastewater treatment facilities.
Residue that is discharged from evaporative cooling systems has heavy concentrations of saline, known as “blowdown.” Levels of sodium are “already of some concern” in the 590-square-mile Occoquan River watershed, although less so in the Potomac River basin, the report notes.
The report makes three recommendations to the Board of Supervisors on addressing the potentially heavy water demands for data centers:
- Consider ways of possibly cutting off water for data center use during periods of drought
- Find ways to use recycled wastewater rather than fresh water for cooling
- Set rules prohibiting the return of saline-laden water in areas served by the Occoquan Reservoir
On another water-related topic, the EQAC report urges county leaders to stay in front of new Environmental Protection Agency (EPA) rules limiting PFAS residue in drinking water provided to homes and businesses.
An acronym for per- and poly-fluoroalkyl substances, PFAS are manmade chemicals in use since the 1940s. The tightening of EPA rules could require Fairfax Water to make upgrades nearing a half-billion dollars by 2029.
When the new limits were announced, Fairfax Water officials acknowledged in a statement last April that PFAS need to be addressed:
“Due to decades of use, PFAS are everywhere in the environment. Industrial sites might release PFAS into the water or air. Consumer and household products containing PFAS enter landfills and are washed down the drain. Because of their chemical composition, PFAS do not break down naturally and can be found throughout the environment in surface water, groundwater, air and soil. They build up in the environment over time, eventually entering our bodies through food and drinking water.”
Without an easing of the new regulations, or financial support for upgrades from the federal or state governments, the cost to address PFAS will be borne by Fairfax Water customers.
The EQAC report doesn’t offer specific proposals on PFAS, but urges Fairfax Water to set its rate for customers at a level high enough to cover expected costs of purchasing, installing and maintaining equipment needed to meet the EPA’s regulations by the deadline.
A public hearing on the annual EQAC report will be held this Wednesday, Jan. 8 at 7:15 p.m. at the Fairfax County Government Center.
Comment will be accepted in person as well as virtually (either live or through a recorded video). Written testimony also will be accepted through Jan. 8.
