Potomac River Leads 2026 List of America’s Most Endangered Rivers® Due to Historic Sewage Spill and Unchecked Data Center Growth

Contact:
Hawk Hammer, National Communications and Media Director, Hhammer@americanrivers.org
Fritz Schneider, Director of Communications, 301-728-4811, fritz@prknetwork.org
Lisa Goodnight, Communications Manager, 301-450-1478, lisa.goodnight@natureforward.org

Washington, D.C. — American Rivers is today naming the Potomac River as number one on our America’s Most Endangered Rivers® list of 2026, because of the one-two-punch of a historic sewage spill and the rapidly expanding footprint of water-intensive data centers across the watershed, threatening water availability and water quality of the “nation’s river”. 

“As the backdrop to our nation’s capital, the Potomac should reflect the highest standards of water health and stewardship,” said Pat Calvert, Virginia conservation director for American Rivers. “The Potomac is at an inflection point and cannot continue to sustain the rapid expansion of water-guzzling data centers drawing from its waters. Act now or watch this river be detrimentally redefined for the everyday citizen that depends on it.”

The Potomac River basin is home to more than six million people across Maryland, Virginia, West Virginia, Pennsylvania, and Washington, D.C. Flowing more than 380 miles from the Appalachian Highlands to the Chesapeake Bay, the Potomac is the primary source of drinking water for the nation’s capital and many surrounding communities. It is internationally renowned for its fisheries and recreation opportunities. 

“The Potomac is our Nation’s River,” said Betsy Nicholas, president of Potomac Riverkeeper Network. “We must do all we can to protect it for this generation and those to come. We urge that lawmakers and regulators require investigation into data centers’ water use, toxins associated with them, and impacts on affected communities before hasty approvals of their construction cause irreparable harm.”

The Potomac watershed is experiencing a dramatic surge in data center development, particularly in Northern Virginia and parts of Maryland. The region, which earned the nickname “Data Center Alley”, already hosts more than 300 data centers, with projections suggesting that as many as 1,000 facilities could occupy nearly 20,000 acres of land in the state in the coming years—the equivalent of roughly 3,500 football fields. 

“Data Centers are developing in our region with few regulations or accountability for how they use or impact the Potomac watershed. This rapidly developing industry threatens the Potomac through both water use and increased pollution,” said Lydia Lawrence, director of conservation for Nature Forward.

Such scale and pace of data center expansion is occurring without watershed-wide analysis, which masks its combined impacts on stormwater runoff, chemical spill response, management of hazardous materials, groundwater withdrawals, and flood risk. In many cases, there is little to no requirement for advanced stormwater treatment, long-term remediation planning, or disclosure of water use and discharge data for projects. Many proposed facilities are upstream of drinking water intakes that serve millions of people. 

“Now is the time to advocate for the strongest protections possible for the Potomac River, continued Lawrence. “This river, a critically important natural resource for the people and wildlife in our entire region, faces serious threats from unchecked data center development and the Potomac Interceptor pipeline spill. We urge Federal, state, and local legislators to take swift action and pass policies that protect the immediate and future health of the Potomac.”

“The Potomac Interceptor failure was a wake-up call: hundreds of millions of gallons of sewage polluted this river, and our communities are still waiting for answers,” said David Flores, vice president and general counsel for Potomac Riverkeeper Network. We are working to ensure long-term impacts are fully addressed and that ongoing, transparent water quality monitoring continues.” 

The pressures on the river reached a tipping point after the failure of the Potomac Interceptor sewage line earlier in the year, when roughly 200–300 million gallons of untreated sewage spilled into the river. Bacteria levels near the spill site reached nearly 12,000 times the safe recreational limit. 

“This crisis makes one thing clear,” said Nicholas. “Failing wastewater infrastructure is polluting our rivers. Aging pipes are breaking, and without real investment and oversight, including federal and state investment, it will happen again. We need immediate action to fix these systems and ensure accountability, monitoring, and long-term restoration of the Potomac.”

The historic spill exposed an urgent threat to an already at-risk river: aging wastewater infrastructure. Many pipes around the capital have exceeded their 50-year design life, including the Potomac Interceptor, which is now more than 60 years old.

American Rivers and its partners are calling on Congress to reauthorize critical water infrastructure programs—including the State Revolving Fund and the Sewer Overflow and Stormwater Grant Program—before they expire in 2026. At the same time, leaders in Virginia and Maryland must require stronger safeguards for data center development, including transparency on water use and watershed-wide assessments of cumulative impacts.

For more details on this river and the full America’s Most Endangered Rivers® list of 2026, including the selection process, click here. 

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American Rivers is a national conservation organization working to make every river clean and healthy for people and wildlife. We combine evidence-based solutions with enduring partnerships to safeguard the 4.4 million miles of rivers and streams that are essential to our nation’s clean drinking water, extraordinary wildlife, and the strength of our communities. For more than 50 years, our staff, supporters, and partners have been driven by a common belief: Life Depends on Rivers®. AmericanRivers.org

About Potomac Riverkeeper Network: Potomac Riverkeeper Network is a registered 501(c)(3) non-profit organization with three regional Waterkeeper branches: Potomac Riverkeeper, Upper Potomac Riverkeeper, and Shenandoah Riverkeeper. PRKN’s mission is to protect the right to clean water for all communities and all those who live in and rely upon the Potomac and Shenandoah watersheds by stopping pollution, making drinking water safe, protecting healthy river habitats, and enhancing use and enjoyment for all. For more information, visit our website.

About Nature Forward: Nature Forward inspires residents of the greater Washington, DC region to appreciate, understand, and protect their natural environment through outdoor experiences, education, and advocacy. Founded in 1897 as the Audubon Society of the District of Columbia, Nature Forward has evolved into a leading regional environmental organization serving diverse communities across Maryland, Virginia, and the District of Columbia through education programs, conservation advocacy, and community engagement initiatives.