Riverside County, CA Environmental Rules: Stormwater Management (2026)

In unincorporated Riverside County, it's a violation to throw, deposit, or leave any pollutant in a street, alley, sidewalk, storm drain, catch basin or other drainage structure, or on any public or private lot. Illicit connections and non-stormwater discharges to the storm drain system are also banned. New and existing development must control runoff to prevent water-quality deterioration, using best management practices set by the TLMA director. County inspectors can enter any regulated premises without charge to check compliance. This chapter does not reach the county's 28 incorporated cities, including Riverside, Moreno Valley, Corona and Temecula, which enforce their own municipal stormwater codes.