Washington State Regulations


NPDES and Municipal Stormwater Permits

All municipal, industrial, and commercial facilities that discharge either wastewater or stormwater from a point source to a receiving waterbody must obtain a National Pollutant Discharge Elimination System (NPDES) permit. Such discharges may be permitted either with an individual permit or a general permit.

Washington State's NPDES Municipal Stormwater Permit process is a major regulatory driver for municipal stormwater activity in Washington.

Phase I of the Municipal Stormwater Permit regulates the discharge from municipal separate stormwater sewer systems (MS4s) for incorporated cities with a population greater than 100,000 or unincorporated counties with populations over 250,000. This permit also extends to MS4s owned by public entities located within a Phase I city or County (e.g. the Ports of Seattle and Tacoma).

Phase II of the Municipal Stormwater Permit extends the NPDES program to certain "small" municipalities with MS4s. There are two distinct Phase II permits: one for Eastern Washington and one for Western Washington.

Growth Management Act

The Growth Management Act (Chapter 36.70A RCW) is a Washington State law enacted in 1990 that guides planning for growth and development in The State. It requires that local governments in fast growing or densely populated counties to develop and adopt plans to "protect the environment and enhance the state's high quality of life, including air and water quality, and the availability of water" (RCW 36.70A.020). It requires counties and cities to include the best available science when developing policies and growth regulations. The Department of Commerce offers more information on the Growth Management Act, including update resources, grants, and checklists.

Surface Water Quality Standards

Chapter 173-201A of the Washington Administrative Code (WAC) serves as the basis for protecting and regulating surface water quality in the state. These standards implement portions of the Clean Water Act by specifying the designated and potential uses of waterbodies in the state. The standards set water quality criteria and contains policies to protect high-quality waters. In many cases, the water quality standards specify how criteria are to be implemented. You can learn more about Washington's Surface Water Quality Standards by visiting the Department of Ecology's website.

Washington State Coastal Zone Management (CZM) Program

Washington became the first state to achieve a federally-approved state CZM Program in 1976. Washington's CZM program is based primarily upon our Shoreline Management Act of 1971, as well as other state land use and resource management laws.

Ground Water Quality Standards

Various chemicals used or dumped on the ground's surface or leaked from septic systems can infiltrate into the ground and end up in the ground water.  Once these pollutants enter ground water, they can be difficult to detect by taste or smell, and difficult to remove.  They can then end up in drinking water and water used for irrigation.  Because ground water supplies many of our streams, especially in the late summer, pollutants in ground water can end up in those rivers and streams. You can learn more about Washington's Surface Water Quality Standards by visiting The Department of Ecology's website or Chapter 173-200 of the Washington Administrative Code.