All MS4 communities in Illinois are required to develop a Storm Water Management Program for their community.

So, what is an MS4?

An MS4 is a municipal separate storm sewer system. It is a publicly owned storm sewer system that conveys storm water to a creek or a wetland, rather than a sewage treatment plant. That’s right… the water that lands on the streets and the parking lots in our area flows into a series of drains called catch basins or storm grates. All of that water eventually finds its way, untreated, into local area waterways.

What does the permit require?

As mandated by the Clean Water Act, the General NPDES ILR40 Permit is required of all MS4 communities in order to address stormwater pollution. In order to protect the water quality of our streams, MS4 communities in Illinois are required to develop a Storm Water Management Program for their community. These state mandated plans include six minimum control measures:

  1. Public education and outreach on storm water impacts
  2. Public involvement and participation
  3. Illicit discharge detection and elimination
  4. Construction site storm water runoff control
  5. Post construction storm water management
  6. Pollution prevention/good housekeeping for municipal operations

MS4 communities are required to implement various Best Management Practices (BMPs) and establish measurable goals to satisfy each of the six minimum control measures.

See the “Education Resources” page for a menu of stormwater BMPs that you can implement in your own community.

We encourage you to browse this website to learn more about the NPDES MS4 Program!