Ventura, CA Environmental Rules: Stormwater Management (2026)

Stormwater in Ventura is regulated through three layers. (1) Federal/state: the Clean Water Act (33 U.S.C. §1342) and California's statewide NPDES program implemented by the State Water Resources Control Board. (2) Regional: the Ventura Countywide MS4 Permit covers Ventura and other Ventura County co-permittees, mandating illicit discharge detection and elimination, post-construction LID controls, and construction-site runoff controls. (3) Local: the San Buenaventura Municipal Code (SBMC) implements MS4 requirements through public works and building standards. New and redevelopment projects meeting size thresholds (typically 5,000 sq ft impervious surface for priority categories) must prepare a Stormwater Quality Management Plan (SQMP) demonstrating on-site capture/infiltration via bioretention, pervious paving, biofilters, or cisterns sized to the 85th-percentile 24-hour storm. Non-stormwater discharges (wash water, pool drainage, concrete slurry, chlorinated water, irrigation runoff, oil/grease) to storm drains, gutters, or the Ventura River/Santa Clara River are prohibited. Ventura's beaches and Ventura Harbor make storm-drain pollution a 303(d)-listed concern.