San Bernardino County, CA Environmental Rules: Grading & Drainage (2026)

Grading and drainage work in San Bernardino County is regulated by the Development Code Chapter 83 and the California Building Code Appendix J. Grading permits are required for any excavation or fill exceeding 50 cubic yards, cuts over 5 ft deep, fills over 3 ft deep, or any work in floodplains or on slopes exceeding 15 percent. Applications require site plans, cross-sections, drainage calculations, and erosion control BMPs. Rough grading permits cover mass grading while precise grading permits address pad and lot-specific work. Hillside grading requires geotechnical reports by licensed geotechnical engineers addressing slope stability, surficial stability, and seismic considerations. Drainage must be directed away from structures at 2 percent minimum slope for 10 ft and must not adversely affect adjacent properties under California Water Code 830+. Lot-to-lot drainage changes require easements and downstream owner consent. Retaining walls over 4 ft in height (or over 3 ft with surcharge) require engineered design and building permits. Import/export of soil exceeding thresholds requires truck haul route approval. All grading sites 1 acre or more need SWPPP coverage. Rainfall season (October 15 - April 15) triggers mandatory BMP upgrades.