Grading the Potomac River

Grading the Potomac River

Stormwater runoff pollution remains a major threat.

The Potomac River provides drinking water for 5 million people.

The Potomac River provides drinking water for 5 million people.

Five million people depend on the Potomac River for their drinking water, so you have to wonder, is a grade of B good enough?

Potomac Conservancy scores the Potomac River's health a grade of B, an improvement from a B-minus three years ago, and D in 2011.

The Potomac River is in the middle of a comeback and is much cleaner than it used to be. There’s been great progress to clean up the “Nation’s River,” but pollution remains a problem.

From the report,

The Potomac Conservancy’s Report Card assesses over 20 ecosystem indicator measures for pollution, fish, habitat, land, and recreation. 

Top pollutants (nitrogen, phosphorus, and sediment) are on track to meet 2025 federal reduction goals, making the Potomac River a success story of the broader Chesapeake Bay restoration initiative. The Potomac’s comeback is a testament to decades of hard work to reduce pollution and restore local water quality. 

“The Potomac River is one of the Chesapeake Bay region’s most precious natural resources,” said Potomac Conservancy President Hedrick Belin, adding, “As the source of the water we drink, an economic driver of local fisheries, and home to natural wonders, the Potomac is critically important to our communities and public health. We must do everything we can to continue to reduce pollution and restore the health of our forests and streams.” 


● Industrial and farming pollution are declining. All top pollutants (nitrogen, phosphorus, and sediment) are on track to meet 2025 federal pollution reduction goals. 

● Bald eagles, shad, and local wildlife are rebounding. The Potomac River is one of the only Chesapeake Bay tributaries where shad have successfully recovered. 

● More shoreline(human)  visitors, anglers, and water recreationists are enjoying the Potomac. Sports fishing licenses quadrupled during the pandemic. 


● Polluted urban runoff is the only growing source of pollution to the Potomac River and it threatens decades of restoration progress. Runoff pollutes local waterways with fertilizers, street oils, trash, sediment, and diluted sewage. 

● Rapid deforestation in the region is weakening nature’s defenses against polluted runoff. Among the 20+ ecosystem indicators, streamside forests received one of the worst grades scoring a D+. This signals the region is not meeting its forest protection goals. 

● The climate crisis is straining the local ecosystem from intensifying storms, more intense droughts, rising river levels, and warming stream temperatures. Flash flooding and threats to indigenous trees and vegetation are making it harder to combat polluted runoff. 

The report calls on decision-makers and the community to invest in land-use solutions that reduce polluted runoff and make the ecosystem more resilient to climate change.

“As with all rivers, the Potomac River is only as healthy as the lands that surround it. We can’t bulldoze our way out of our water and climate crises,” said Belin adding, “We must leave behind a 20th-century mindset where we pave over forests and deal with the consequences later. It’s time for leaders to embrace bold, nature-based solutions for the protection of our rivers, drinking water sources, and public health.” 

About the Potomac River: 

● The drinking water source for five million residents in the greater Washington, DC metro area. 

● The second largest tributary to the Chesapeake Bay. Its waters flow over 400 miles and its watershed spans four states (MD, PA, VA, WV) and the District of Columbia. 

● Home to over 1,400 native plants and animals, and 200 globally rare species. 

● Flows over 380 miles through West Virginia, Pennsylvania, Virginia, Maryland, and Washington, DC. 

● Supports a local population of bottlenose dolphins; one of the only witnessed wild dolphin births in the world occurred in the Potomac River in 2019. 

The Potomac River Report Card presents and assesses data on five significant river health indicators: pollution, fish, habitat, land, and people. Data sets for some indicators take time to become publicly available, so we have aggregated and assessed data through 2020. 

Using an established baseline and set of benchmarks, the Conservancy measures restoration progress and assigns the Potomac River a grade. The overall grade has been weighted to account for non-quantifiable, inaccessible, or outdated data on water quality threats. These threats include, but are not limited to, harmful algal blooms, warming waters, endocrine-disrupting compounds, PCBs, aquatic diseases, and others. 

Due to public health concerns, it is currently illegal to swim in the Potomac River and eat its fish in and around Washington, DC. Studies are being conducted to assess whether lifting DC’s swimming ban could be possible in the next two to three years. If that happens, however, the river would still be off-limits during and after wet weather because stormwater runoff causes pollution to spike to dangerous levels.

Pollutants that are harming local waters include:

Toxins and excess nutrients from fertilizers, pesticides, & street oils; silt and sediment, e-coli from sewage and animal waste, other bacteria, algae blooms. Industrial pollution, wastewater effluent, and agricultural runoff are common sources of pollution that are in steady decline.

Polluted urban runoff is the only growing source of pollution to the Potomac River. Polluted runoff occurs when excess rainwater flows across paved and hardened surfaces and carries street oils, lawn fertilizers, trash, and even diluted sewage directly into local streams.

Restoring swimmable and fishable waters to the Potomac River is an ongoing fight — and one that is getting harder.

Rapid deforestation in the region is happening at an alarming rate and directly contributing to increasing polluted runoff. Worse still, efforts at maintaining and replacing streamside trees received a D+ in this report signaling the region’s failure to meet its planting goals.

The climate crisis is intensifying storms and lengthening droughts in our region — extreme conditions that weaken nature’s defenses and increase polluted runoff. Rising river levels, hotter stream temperatures, and changing seasons are putting further strains on the local ecosystem.