San Clemente, CA Environmental Rules: Erosion Control (2026)

Article XII of the city's Grading Ordinance, Chapter 15.36, governs erosion control on every graded site. Section 15.36.320 requires the faces of cut and fill slopes, and the project site generally, to be prepared and maintained against erosion, with the City Engineer able to waive protection only where the cut material itself resists erosion. During the rainy season, defined in the section as October 15th through April 15th, temporary or permanent erosion control devices, desilting basins, check dams or riprap must be employed as the City Engineer approves, and no single permitted grading site may move more than 200 cubic yards of material during that window unless an erosion control system has been approved or waived.

The section also sets specific engineering standards: desilting basins must provide capacity meeting current Orange County Environment Management Agency standards, and where built of compacted earth must reach 90 percent relative compaction, verified by a soil engineering report submitted to the City Engineer. Slopes over five feet high need effective planting unless the City Engineer approves otherwise, and slopes over fifteen feet may need a sprinkler system. Removable protective devices must be in place at the end of each working day whenever the five-day rain forecast exceeds a 40 percent probability. Section 15.36.330 requires an erosion control plan submitted for City Engineer approval by September 15th each year for permitted projects, though single-lot residential projects can skip the plan if an approved system is installed before October 15th. Any violation of a state or federal stormwater permit, or of the city's own water quality requirements under Chapter 13.40, is separately a violation of this article.