Contra Costa County, CA Fence Regulations: Retaining Walls (2026)
Key Facts
- Retaining wall exemption
- Up to 3 feet
- Combined fence + wall
- 7 feet total, wall ≤ 3 ft
- Code Section
- Ord. Code 72-6.202
Summary
Retaining walls up to 3 feet (measured footing to top) are exempt from building permits in unincorporated Contra Costa County. Combined with a fence, the total height may not exceed 7 feet, and the wall portion may not exceed 3 feet.
Retaining walls that are not more than three feet in height, measured from the top of the footing to the top of the wall, and that have a downward slope at the bottom of the retaining wall not exceeding 1(vertical): 10(horizontal), unless supporting a surcharge or ground slope exceeding 1 (vertical): 2 (horizontal) or impounding class I, II, or III-a liquids.
Full Breakdown
Ordinance Code Section 72-6.202, adopting the 2022 California Residential Code exemptions, allows 'Retaining walls that are not more than three feet in height, measured from the top of the footing to the top of the wall, and that have a downward slope at the bottom of the retaining wall not exceeding 1(vertical): 10(horizontal), unless supporting a surcharge or ground slope exceeding 1 (vertical): 2 (horizontal) or impounding class I, II, or III-a liquids.' The county's Fences and Retaining Walls FAQ confirms: 'The maximum height of a retaining wall is three feet. Maximum combination of a fence and retaining wall is seven feet total but the wall may not exceed three feet.' A taller retaining wall, a wall supporting a surcharge, or any wall failing the slope test requires engineered plans and a permit.
Violations & Fines
Constructing a retaining wall over 3 feet, or one that supports a surcharge or impounds hazardous liquids, without a permit violates Section 72-6.202. Enforcement may include stop-work orders, mandatory engineered drawings, after-the-fact permitting, and removal in cases of failed walls threatening neighboring property.
Frequently Asked Questions
Can I stack a fence on top of a 3-foot retaining wall?
When does a retaining wall need an engineered permit?
Sources & Official References
Other rules in Contra Costa County
California rules heatmap·Compare Contra Costa County to another location·View the California fence regulations overview
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