Riverside County, CA Environmental Rules: Erosion Control (2026)

Under Riverside County Ord. 457 (Regulating Grading, Erosion and Sediment Control), any site with active grading must have an approved Erosion and Sediment Control Plan (ESCP) filed with and approved by the County Building and Safety Department. Plans must address: (1) perimeter controls (silt fence, fiber rolls, gravel bags); (2) stabilized construction entrances to prevent track-out; (3) soil stabilization on all disturbed slopes (hydromulch, blankets, straw mulch) within 7-14 days of inactivity; (4) sediment traps or basins for sites over 1 acre; (5) concrete washout containment; (6) dust control via water trucks, soil binders, and wind fencing, meeting SCAQMD Rule 403 and Mojave Desert AQMD Rule 403.1. Between October 1 and April 30 (wet season), all sites must have full erosion controls installed and a rain-event action plan (REAP) prepared. Track-out onto public streets is prohibited and triggers immediate cleanup under Ord. 457 and the MS4 permit. Penalties for grading or erosion violations begin at $500 and escalate; stop-work orders are routine. Grading on steep slopes (over 3:1) or in floodplains requires supplemental geotechnical review and compliance with Ord. 458 (Drainage) and Ord. 460 Art. III (Fault Hazard).