Data Centers Could Double Potomac Water Use

 FTX Now, Fairfax environmental council worried about data centers’ impact on local water supply

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:

1. Consider ways of possibly cutting off water for data center use during periods of drought
2. Find ways to use recycled wastewater rather than fresh water for cooling
3. Set rules prohibiting the return of saline-laden water in areas served by the Occoquan Reservoir

Eventually, the Potomac River, like the mighty Colorado River, might be used up by the time it reaches Great Falls at Washington D.C., or merely a trickle of hyper saline water. That won't be bad for the environment at all, am I right?