Regional MS4 Permit Adopted July 23, 2021

The Los Angeles Regional Water Quality Control Board adopted the Regional Phase I Municipal Separate Storm Sewer System (MS4) National Pollutant Discharge Elimination System (NPDES) Permit, Order No. R4-2021-0105 (Permit), on July 23, 2021 and it became effective on September 11, 2021. The Permit applies to Ventura and Los Angeles Counties and all incorporated cities therein, and supersedes the three Orders that previously covered the area, R4-2010-0108 (Ventura County), R4-2012-0175 (L.A. County except for the City of Long Beach), and R4-2014-0024 (City of Long Beach). Many decisions and actions are required of the permittees in the first 30 months following the Permit effective date. Key among them are deciding whether to implement a Watershed Management Program, Monitoring Program coordination, and filing the corresponding Notices of Intent. See the new Permit for details.