What is a Municipal Separate Storm Sewer System (MS4)?
The regulatory definition of an MS4 (40 CFR 122.26(b)(8)) is " a conveyance of system of conveyances (including roads with drainage systems, municipal streets, catch basins, curbs, gutters, ditches, man-made channels or storm drains): (i) Owned or operated by a state, city, town, borough, county, parish, district, association, or other public body (created to or pursuant to sate law) including special districts under state law such as a sewer district, flood control district or drainage district, or similar entity, or an Indian tribe or an authorized Indian tribal organization, or a designated and approved management agency under section 208 of the Clean Water Act that discharges into waters of the United States. (ii) Designed or used for collecting or conveying storm water; (iii) Which is not a combined sewer; and (iv) Which is not part of a Publicly Owned Treatment Works (POTW) as defined at 40 CFR 122.22."

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1. What is Storm Water?
2. Why is storm water important?
3. What is an NPDES (National Pollutant discharge Elimination systems) permit?
4. What is a pollutant?
5. Do I need an NPDES permit?
6. Where do I apply for an NPDES permit?
7. What is a Municipal Separate Storm Sewer System (MS4)?