Potomac most endangered river as data centers drain water

American Rivers released its 2026 list of most endangered rivers, naming the Potomac River as the top endangered river due in large part to uncontrolled data center growth throughout the watershed.

• Main announcement: American Rivers’ 2026 Most Endangered Rivers list places the Potomac River first, citing uncontrolled data center growth in the Loudoun County watershed; data centers in Loudoun account for about 2–3% of basin withdrawals (up to 8% in peak summer months) and represent 9% of annual consumptive use (up to 12% in summer).
• Context and policy detail: The piece references that the Virginia General Assembly passed SB 553 this spring, which will require utilities to report monthly water usage by data centers to the Department of Environmental Quality (DEQ); advocates note the law does not require facility-level disclosures or peak-daily usage reporting and call for stronger, statewide tracking and transparency.