Potomac River Now Ranks as the Most Endangered River in U.S.

The Potomac River has been designated the country's most endangered river for 2026 by conservation organization American Rivers, according to a new report. The organization identified two primary threats: a massive sewage spill in January 2026 that released between 200 and 300 million gallons of wastewater, and the rapidly expanding footprint of water-intensive data centers in the region. The sewage spill highlighted the urgent issue of aging wastewater infrastructure, with many pipes, including the Potomac Interceptor, exceeding their 50-year design life. David Flores, vice president and general counsel for Potomac Riverkeeper Network, emphasized that the incident was a "wake-up call" and that communities are still seeking answers. American Rivers also raised concerns that the unchecked expansion of data centers is occurring without adequate watershed analysis. The report noted that data centers often face no requirements for stormwater treatment, remediation planning, or disclosure of their substantial water use, which is necessary for cooling IT systems. Lydia Lawrence, director of conservation for Nature Forward, stated that this rapidly developing industry threatens the Potomac through both water consumption and increased pollution due to a lack of regulation and accountability. A recent study by the Interstate Commission on the Potomac River Basin further corroborated these findings, indicating that continued data center growth could significantly strain water resources. The report also listed other endangered rivers, including California's San Joaquin River and the Dan River in southern Virginia.