By definition, a Municipal Separate Storm Sewer System (MS4) is a conveyance or system of conveyances otherwise known as a municipal separate storm sewer system, including roads with drainage systems, municipal streets, catch basins, curbs, gutters, ditches, manmade channels, or storm drains:

1. Owned or operated by a federal, state, city, town, county, district, association, or other public body, created by or pursuant to state law, having jurisdiction or delegated authority for erosion and sediment control and stormwater management, or a designated and approved management agency under section 208 of the Clean Water Act (CWA) that discharges to surface waters;
2. Designed or used for collecting or conveying stormwater;
3. That is not a combined sewer; and
4. That is not part of a publicly owned treatment works.

Operators of large, medium, and regulated small Municipal Separate Storm Sewer Systems are required to obtain permit coverage in order to discharge pollutants to state waters. The large, medium and small designations are based on urbanized areas as determined by census data. JMU has been designated as a small MS4 and has obtained general permit coverage which requires the development of a program plan to cover the following minimum control measures:

• Public education and outreach on stormwater impacts
• Public involvement/participation
• Illicit discharge detection and elimination (IDDE)
• Construction site stormwater runoff control
• Post-construction stormwater management in new development and development on prior developed lands
• Pollution prevention/good housekeeping for municipal operations