Norwalk, CA Environmental Rules: Stormwater Management (2026)

04, the 'City of Norwalk Stormwater Management and Discharge Control ordinance,' to meet that permit's requirements. 070 prohibits illicit connections and illicit discharges to the MS4 storm drain system (A), littering refuse into any street, alley, storm drain, catch basin or drainage structure (B), and dumping leaves, dirt or landscape debris into the storm system (C). Ten specific non-stormwater discharges are separately banned unless covered by their own NPDES permit or a Regional Board exemption, including untreated wash water from gas stations and auto repair shops, wastewater from mobile auto or carpet washing operations, runoff from leaking vehicle repair areas, commercial pool filter backwash, washout from concrete trucks, and disposal of banned pesticides or hazardous waste in a way that threatens the MS4 (D).

Car washing is restricted: vehicles may only be washed at a commercial car wash, by a resident using a hand-held bucket or a hose with an automatic shutoff nozzle so water does not reach the street, or at an approved fleet car wash facility (E). 090 additionally require industrial/commercial parking lots over 25 spaces to be swept regularly to control debris exposed to stormwater.