Basic Information: What is the Problem?

Harmful algal blooms are one effect of excessive nitrogen and phosphorus in water bodies.

Nitrogen and phosphorus pollution is caused by excessive amounts of nitrogen and phosphorus entering our water bodies from many different sources. Nitrogen and phosphorus pollution has consistently ranked as one of the top causes of degradation in U.S. waters for more than a decade and affects all types of water bodies across the United States, including lakes, streams, rivers, estuaries, and oceans.

Everyone Can Make a Difference—Even You!

The most effective way to combat nitrogen and phosphorus pollution is to first gain a good understanding of the problem and learn why nitrogen and phosphorus pollution happens. This knowledge supports us as we take action to help reduce the amount of nitrogen and phosphorus that enter local water bodies.

What EPA and the States are Doing to Reduce Nitrogen and Phosphorus Pollution

EPA is committed to reduce the amount of nitrogen and phosphorus entering our water bodies and to prevent the harmful effects that this pollution has on water quality. Some of the actions EPA has taken to achieve this goal include:

• Working with states, territories, and authorized tribes to help protect our nations waters
• Providing funding for projects that focus specifically on the problem of nitrogen and phosphorus pollution
• Providing guidance and technical support for the development of criteria

Learn more about what EPA and the States are doing to reduce nitrogen and phosphorus pollution