On January 29, 2010, the Santa Ana Regional Water Quality Control Board issued a fourth-term area wide National Pollutant
Discharge Elimination System (NPDES) Municipal Separate Storm Sewer System Permit (MS4 Permit) to the Riverside County
Flood Control and Water Conservation District (the Principal Permittee), the County of Riverside and the Cities of Beaumont,
Calimesa, Canyon Lake, Corona, Hemet, Lake Elsinore, Moreno Valley, Menifee, Norco, Perris, Riverside, San Jacinto and Wildomar
The Santa Ana MS4 Permit is for the portion of the Santa Ana River watershed located within Riverside County
(Order No. R8-2010-0033, NPDES Permit No. CAS618033). The Permittees’ stormwater programs are designed to ensure compliance with this permit.
On June 7, 2013 the Santa Ana Regional Water Quality Control Board amended the permit
(Order No. R8-2013-0024) to include the Cities of Eastvale and Jurupa Valley.
On January 29, 2015 the Permittees received an administrative extension of the Riverside County Municipal Stormwater Permit
(NPDES No. CAS618033) from the Santa Ana Regional Water Quality Control Board.