Stormwater Management

Let us know your thoughts, complaints or questions on the County’s Stormwater Management Program.

Missoula County is seeking public comment, questions and complaints on stormwater management to help prevent contamination of the Missoula Valley aquifer, the only source of drinking water for all of Missoula’s residents. Stormwater management is crucial for public health, safety, water quality, wildlife habitat and future development.

The Federal Environment Protection Agency and Montana Department of Environmental Quality require urbanized areas (populations of 10,000 people or more) to obtain a Municipal Separate Storm Sewer System (MS4) permit to discharge stormwater into state waters. This permit requires areas to establish a Stormwater Management Program to reduce pollution from stormwater runoff. The program details the stormwater management activities the County performs, including control techniques and practices, systems, designs, good standard engineering practices and other such provisions for controlling water pollutants.

It also must include six specific methods for improving stormwater quality:

1. Public education and outreach
2. Public involvement and participation
3. Illicit discharge detection and elimination
4. Construction site runoff control
5. Post-construction runoff control
6. Pollution prevention and good housekeeping

Missoula County’s current MS4 permit extends through 2027.