La Mesa, CA Environmental Rules: Erosion Control (2026)

The City of La Mesa regulates construction-site erosion and sediment control under Municipal Code Chapter 7.18, Storm Water Management and Discharge Control. Section 7.18.100 directs the city engineer to write and enforce Best Management Practices (BMPs) for construction activity, and each site is ranked high, medium or low threat to water quality based on soil erosion potential, site slope, project size and type, and proximity to receiving waters. Those BMPs live in the city's Storm Water BMP Manual, incorporated by reference into the chapter. Section 7.18.140(A) sets the numeric trigger: before the rainy season, dischargers must remove or secure significant accumulations of eroded soil from previously disturbed slopes, and any slope more than five feet high, larger than 250 square feet, and steeper than 3:1 (run to rise) that has been cleared, graded or landscaped must be continuously protected from erosion.

A project can leave open only as much cleared or graded acreage as it can protect before a predicted storm, or seventeen acres, whichever is less, unless the city engineer approves a larger area in writing. The same section requires parking lots to get at least one thorough dry-sweep cleaning every September and all stockpiled soil covered and contained year-round. The city engineer can inspect any site under Section 7.18.160, order sampling and monitoring under Section 7.18.150, and require a site-specific local Storm Water Pollution Prevention Plan under Section 7.18.180 when BMPs are not enough.

Watercourse work within thirty feet of a creek centerline or twenty feet of the top of a bank needs a separate city engineer permit under Section 7.18.200.