Los Angeles, CA Environmental Rules: Erosion Control (2026)
Key Facts
- Erosion control completion deadline
- Within 30 days of grading cessation (no active building permit)
- Interceptor terrace minimum width
- 8 feet (2438.4 mm)
- Interceptor terrace vertical spacing
- Maximum 25 feet (measured along a vertical plane)
- Maximum single terrace run
- 150 feet to a down drain
- Diverter terrace trigger
- Uphill tributary area > 10% slope and > 40 ft horizontal projection
- Ground cover protection zone
- Any hillside watershed: no removal except under permit
Summary
Hillside grading that disturbs vegetative ground cover requires erosion control to be completed within 30 days of work stoppage. Cut and fill slopes must have paved interceptor terraces installed every 25 vertical feet.
91.7005.3. Removal of Ground Cover. The existing vegetative ground cover of any watershed in any hillside area shall not be destroyed, removed or damaged except pursuant to lawful grading, use or occupancy of the property. Except for California native oak, bay, black walnut and sycamore trees regulated by the provisions of Article 7 of Chapter I or Article 6 of Chapter IV of the Los Angeles Municipal Code, removal of trees and shrubbery will be allowed where such work will not disturb the turf, sod or other existing vegetative ground cover. Whenever such ground cover is removed or damaged pursuant to a grading permit, the permittee shall restore and maintain approved ground cover, or shall accomplish such other erosion control protection as is required. Such erosion control shall be completed within 30 days after cessation of the grading work where no valid building permit is in effect for the site.
91.7013.1. Interceptor Terraces. Paved interceptor terraces shall have a minimum width of 8 feet (2438.4 mm) and shall be installed on the face of all cut and fill slopes at intervals not to exceed 25 feet (7.620 m) measured along a vertical plane. Where only one terrace is required, it shall be at mid-height. A single run of an interceptor terrace shall not exceed 150 feet (45.72 m) to a down drain.
Full Breakdown
LAMC § 91.7005.3 prohibits destruction or removal of existing vegetative ground cover in hillside watersheds except under a lawful grading or occupancy permit. Whenever ground cover is disturbed by grading, the permittee must restore approved ground cover or install alternative erosion control within 30 days after grading ceases (where no active building permit exists). LAMC § 91.7013.1 requires paved interceptor terraces, at least 8 feet wide, on the face of all cut and fill slopes at intervals not exceeding 25 vertical feet. Individual terrace runs may not exceed 150 feet before connecting to a down drain. Diverter terraces must be installed at the top of graded slopes where the uphill tributary area exceeds 40 feet and has a slope greater than 10 percent (§ 91.7013.2). Roof drainage must also be conveyed to a street or approved facility via non-erosive means.
Violations & Fines
Failure to install and maintain erosion control devices is a building code violation enforceable by the Superintendent of Building. Under § 91.7005.6, property owners must maintain all retaining walls, drainage structures, and protective devices shown on approved plans.
Frequently Asked Questions
If I stop grading partway through the job, how quickly must I control erosion?
What is an interceptor terrace and when is it required?
Can I remove native plants or lawn to grade my hillside lot?
Sources & Official References
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Erosion Control in Nearby Cities
How other cities in Los Angeles County handle erosion control.