Region 3

Region 3 of the U.S. Environmental Protection Agency includes Delaware, Maryland, Pennsylvania, Virginia, West Virginia, and the District of Columbia. The Region's 29 million people live in densely populated areas such as Baltimore, Washington D.C., and Philadelphia, as well as dispersed rural communities throughout the Region. Region 3 has 177,000 miles of rivers and nearly 415,000 acres of lakes and reservoirs. Principal water bodies include the Delaware Bays, the Chesapeake Bay (whose watershed of 64,000 square stretches across the entire Region), and the Chesapeake Bay's tributaries, such as the Potomac, Patuxent, Susquehanna, and James Rivers. Nitrogen and phosphorus loadings to the Chesapeake Bay are a regional water quality concern, and sources include all major pollutant sectors such as agriculture, forestry, industry, and urban wastewater and runoff.

Nitrogen and phosphorus have always been a part of the Chesapeake Bay ecosystem, but have increased to excessive levels over the last few decades. Prior to substantial human activity in the region, most nitrogen and phosphorus was absorbed or retained by natural forest and wetland vegetation. However, the activities of over 13.6 million people in the watershed have overwhelmed the Chesapeake Bay with excess nitrogen and phosphorus. This comes from a wide range of sources, including sewage treatment plants, industrial facilities, agricultural fields, and residential lawns—even the atmosphere. As forests and wetlands are replaced by farms, cities, and suburbs to accommodate a growing population, nitrogen and phosphorus pollution to the Chesapeake Bay has greatly increased.

Visit EPA's ATTAINS website or the state's water resource agency to learn how nitrogen and phosphorus pollution has affected the state's water bodies.