Carson, CA Environmental Rules: Grading & Drainage (2026)

Carson's Building Code (CMC Article 8) adopts the California Building Standards Code (Title 24 CCR) by reference, including Appendix J — Grading. Appendix J §J103 requires a grading permit for any grading project, with limited exemptions for small residential excavation/fill under 50 cubic yards or for minor work that does not alter drainage. Appendix J §J109 (Drainage and Terracing) requires that finished grades direct surface water away from foundations at a minimum 5% slope for the first 10 feet (or via approved swales), that drainage be carried to an approved point of disposal, and that water not be allowed to pond or drain onto adjacent property. Appendix J §J108 sets minimum cut and fill slope ratios (typically 2:1 horizontal-to-vertical for fills, 1:1 or 2:1 for cuts depending on soils) and requires preventive erosion measures. Carson's mostly flat terrain means most grading projects involve site leveling, foundation pads, and drainage swales rather than slope construction. Stormwater conveyance must connect to the city-approved storm drain system per CMC Art. 4 Ch. 8, and new development must implement Low Impact Development (LID) BMPs to capture and infiltrate or treat the design storm before discharge.