Overview
- American Rivers, which released its annual list Tuesday, ranked the Potomac No. 1 due to a massive January sewage failure and rapid data‑center expansion across the watershed.
- A rupture in the Potomac Interceptor sewer line sent an estimated 200 to 300 million gallons of raw sewage into the river, which American Rivers called the largest U.S. sewage spill on record, pushing bacteria far above safe levels and leading to weeks of warnings.
- D.C. officials ended their river recreation advisory in early March after tests showed the main stem within safe ranges, though advocates still found dangerous E. coli in at least one nearby creek after the break.
- Advocates are pressing Congress to renew key water‑infrastructure programs by September and urging Maryland and Virginia to tighten reviews before approving more data centers.
- The region hosts hundreds of data centers already, and the Potomac Riverkeeper Network says roughly 1,200 more are proposed or in permitting, raising concerns about heavy cooling water use, wastewater discharges, and the security of a water source that serves millions.