Del Norte County, CA Fence Regulations: Retaining Walls (2026)

Del Norte County enforces the California Building Code for retaining walls in the unincorporated area through its Building Inspection Department. Under CBC Section 105.2, a retaining wall is exempt from a building permit only when it is 'not over 4 feet measured from the bottom of the footing to the top of the wall, unless supporting a surcharge or impounding Class I, II or III-A liquids.' A wall taller than four feet, or any wall that holds back a sloped backfill, driveway, structure, or other load (a surcharge), requires a building permit and typically engineered plans. Del Norte's terrain - steep coastal bluffs, river benches, and hillside parcels - makes retaining walls common, and geotechnical review may be required even near the exemption threshold. Two additional layers apply. First, zoning: a wall that functions as a fence or structure must respect the Title 20 height rules in Section 20.48.70 and the yard setbacks in Section 20.48.90. Second, location: within the certified coastal zone, a retaining wall is 'development' under Title 21 and the Local Coastal Program, so a Coastal Development Permit may be required - especially for walls affecting bluffs, drainage, or coastal resources. Confirm requirements with both the Building Inspection Department (707-464-7253) and the Planning Division (707-464-7254) before construction.