Lake County, CA Fence Regulations: Retaining Walls (2026)

The County of Lake Community Development Department interprets retaining walls under California Building Code Section 105.2. A building permit is NOT required for retaining walls not over four (4) feet in height, measured from the bottom of the footing to the top of the wall, unless the wall supports a surcharge or impounds Class I, II or III-A liquids. A building permit IS required for any retaining wall that (a) measures more than four feet from the bottom of the footing to the top of the wall, or (b) supports a surcharge or impounds those liquids. Permitted walls require structural calculations and drawings showing the wall and footings, stamped and signed by a licensed architect or engineer, plus a site plan showing the wall location and setbacks. The County notes a common misconception that any wall up to four feet of exposed height is exempt regardless of back-slope; under the interpretation the relevant measurement is from the footing, and a level grade must be maintained away from the wall to avoid a surcharge. Tiered walls that are not adequately offset are treated as one combined wall. On the zoning side, Zoning Ordinance Section 42.9(f) provides that retaining walls of three (3) feet in height or less need not meet the code's yard setback requirements; walls greater than three feet may be approved pursuant to Sections 42.11 and 42.14.