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

San Bernardino Municipal Code adopts the California Building Code Appendix J for grading and drainage regulation. A grading permit is required for excavation or fill exceeding 50 cubic yards, cut or fill exceeding 3 feet in depth, or any grading on slopes steeper than 3:1 (horizontal to vertical). Minor grading below these thresholds for landscaping or a single-family driveway is typically exempt but must still maintain positive drainage. Applications require a grading plan prepared by a California-licensed civil engineer showing existing and proposed contours, cut/fill quantities, drainage patterns, erosion controls, and slope stability. The California Residential Code requires a minimum 6-inch fall within the first 10 feet from the foundation of a new structure to direct surface water away from the building. Lot drainage may not concentrate flow onto adjacent properties in a way that causes damage, under California Civil Code 1714 negligence principles and the common-law rule of reasonableness for modified surface drainage (Keys v. Romley). Retaining walls over 4 feet in height require a separate building permit and engineering, and walls over 3 feet supporting a surcharge also require permit review. Hillside overlay areas in the foothills trigger additional geotechnical review, slope density limits, and fuel modification zones under the California Fire Code. Swale grading to direct water to approved storm drains or landscape infiltration areas is required for major projects, and stormwater LID features may double as grading drainage solutions.