Jun 6, 2025 · MS4 Resources Fact Sheet (pdf) (1.06 MB) - Overview of outreach materials and funding resources available from EPA.

By definition an MS4 is a system of conveyances that include, but are not limited to, catch basins, curbs, gutters, ditches, man-made channels, pipes, tunnels, and/or storm drains that discharge …

Dec 14, 2024 · A municipal separate storm sewer system (MS4) is a publicly-owned conveyance or system of conveyances (i.e., ditches, curbs, catch basins, underground pipes, etc.) …

Local public entities that own or operate municipal separate storm sewer systems (MS4) play a key role in preventing stormwater runoff from harming Minnesota’s valuable water resources.

Maryland’s Phase II program now covers over 90 small MS4 operators. The Phase II MS4 permits are similar to Phase I permits in that they require implementing stormwater best management …

PennDOT has an Individual MS4 Permit covering stormwater conveyances operated by PennDOT and used for collecting or conveying stormwater runoff associated with PennDOT's roads, …

Jun 13, 2023 · What is an MS4? MS4 is short for "Municipal Separate Storm Sewer System," where the word “Municipal" refers to a unit of local government like a borough or a township, …

The General Permit for the Discharge of Stormwater from Small Municipal Separate Storm Sewer Systems ("MS4 General Permit") regulates stormwater discharges from storm sewer systems …

Jun 1, 2025 · There are approximately 7,250 permitted Municipal Separate Storm Sewer Systems (MS4s), including large and small MS4s that exist nationwide, operating under a National …

An MS4 is a system of drainage (including roads, storm drains, pipes, and ditches, etc.) that is not a combined sewer or part of a sewage treatment plant. During wet weather, pollutants are …