American Rivers has named the Potomac River — the primary drinking water source for the Washington, D.C. metro area, with more than six million people in the broader basin — the nation's most endangered river. The designation cites two converging threats: a January sewage pipe failure that spilled 243 million gallons into the river, and the ongoing expansion of more than 300 data centers across the Northern Virginia watershed.
The Interstate Commission on the Potomac River Basin reported earlier this year that while data centers account for just 1% of total water withdrawals in the D.C. metro area, they represent 9% of annual consumptive use — water permanently removed from the watershed, mostly through cooling tower evaporation — and up to 12% of consumptive use during summer months when residential demand is also highest. That distinction matters: total withdrawals include water returned to the river after use, while consumptive use measures permanent loss. As more centers come online, those percentages are projected to climb.
Northern Virginia hosts roughly 70% of U.S. data center capacity. Dominion Energy, the region's primary utility, has an infrastructure plan calling for approximately 24 GW of new generation and transmission through the mid-2030s — a $40–50 billion capital program driven largely by data center load growth.