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What is NPDES?

The National Pollutant Discharge Elimination System (NPDES) program controls water pollution by regulating the pollutant's source, i.e. pipes, ditches, containers, and other confined means of transport. The goal of this program is to maintain our lakes, ponds, rivers, streams, and creeks so they are safe for drinking, fishing, swimming, and other recreational activities. Homes that are connected to a municipal system or use a septic system do not need an NPDES permit; however, industrial, municipal, and other facilities must obtain permits if they discharge directly to surface waters.

The state-managed NPDES Permit Program regulates substances such as chlorine, metals, minerals, etc., that pose threats to public health. Since its introduction in 1972, the permitting program has been responsible for significant improvements to water quality across the country.

Learn more about NPDES from the U.S. Environmental Protection Agency (EPA) here and the Michigan Department of Environment, Great Lakes, and Energy here.


Phase I is the first phase of the NPDES permit program, which affects municipalities with a population of more than 100,000. In Genesee County, only the City of Flint meets those requirements.


The Phase II NPDES Permit Program expands Phase I by requiring municipal storm sewer systems and construction sites to implement programs and practices to control polluted stormwater runoff. Phase II is the next step in the EPA’s effort to protect, preserve, and improve our water resources. In Genesee County, the Phase II Stormwater Education Program is implemented through collaboration among local units of government and public organizations. This partnership brings together regulated units of government including townships, cities, and villages with local partners who are working to protect our communities’ natural resources. This partnership facilitates our community’s compliance with federal regulation while supporting organizations that are currently working in our communities to positively impact water quality.

What is NPDES?