To enjoy the best of the river, it needs to be healthy. Like all rivers, the health of the Potomac is gauged by the quality of its waters. Water quality is the sum of the biological, chemical, and physical characteristics of a waterway, and the level of interaction between the characteristics. The Clean Water Act of 1972 requires the national water quality inventory. First, the state defines the "designated use" of each stream, river, lake, and estuary within its jurisdiction. Designated uses include aquatic life support, fish consumption, shellfish harvesting, swimming, and provision of drinking water, and a water body may be assigned more than one use. States develop a different set of water quality standards for each designated use designed to protect that use. The results of the 2002 National Water Quality Inventory are a useful tool for painting a picture of the overall health of the surface waters in a given state. The results let us know how much of the state's surface waters are healthy enough to be used the way the state believes they should be used.
- Of the approximately 4,335 miles of Potomac watershed streams and rivers in the state of Maryland, Maryland assessed about 2,828 miles, or 65%.
- Of the miles of river and stream assessed, Maryland found 34% to be good, and 66% to be impaired.
- Of the approximately 5,833 miles of Potomac watershed streams and rivers in the state of Virginia, Virginia assessed 100% of them.
- Of the miles of river and stream assessed, Virginia found 76% to be good, 6% to be threatened, and 18% to be impaired.
- Of the approximately 2,671 miles of Potomac watershed streams and rivers in the state of West Virginia, West Virginia assessed about 1,326, or 50%.
- Of the miles of river and stream assessed, West Virginia found 55% to be good, and 45% to be impaired.
District of Columbia:
- Of the approximately 45 miles of Potomac watershed streams and rivers in the District of Columbia, DC assessed about 32.1, or 71%.
- Of the miles of river and stream assessed, DC found 100% to be impaired.
Other Resources The Interstate Commission on the Potomac River Basin (ICPRB) www.potomacriver.org collects data on the Potomac River and tributaries.In its assessments and ratings of the Chesapeake Bay, the Chesapeake Bay Program issues reports that include information about the health of the Potomac River and its effect on the health of the bay.