Marin County, CA Fence Regulations: Retaining Walls (2026)
Key Facts
- Code Section
- Marin Co. Dev. Code § 22.20.052
- Inward-Facing Wall Max
- 6 feet above grade
- Outward-Facing Wall Max
- 4 feet (8 ft if 25+ ft from property lines)
- Building Permit Threshold
- Walls over 4 ft (footing to top)
Summary
Retaining walls in unincorporated Marin County may reach 6 feet above grade when the exposed face points inward, or 4 feet when facing outward (8 feet if 25+ feet from all property lines), under Development Code § 22.20.052.
Retaining walls may reach a maximum height of six feet above grade if the exposed face of the retaining wall faces into the center of the property. Retaining walls may reach a maximum height of four feet above grade if the exposed face of the retaining wall faces outward from the center of the property, unless they are at least 25 feet from all property lines, in which case they can reach a maximum height of 8 feet above grade.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Municipal Code: Supplement 2026 Update 1).
Full Breakdown
Marin County Development Code § 22.20.052 (Retaining Wall Standards) governs retaining walls separately from fences. A retaining wall whose exposed face points toward the interior of the property may reach a maximum height of 6 feet above grade. A retaining wall whose exposed face points outward (away from the center of the property) is limited to 4 feet above grade unless it is set back at least 25 feet from all property lines, in which case the maximum is 8 feet. Multiple stepped or terraced walls may be treated as a single wall for height calculation purposes. Retaining walls over 4 feet measured from the bottom of the footing to the top of the wall require a building permit per the California Building Code adopted by Marin Title 19.
Violations & Fines
Walls exceeding the height limits or built without required permits are subject to stop-work orders, after-the-fact permits, and removal demands. Structurally inadequate walls may also be cited as unsafe under Title 19.
Frequently Asked Questions
How tall can a retaining wall be in unincorporated Marin?
Do retaining walls need a building permit?
Sources & Official References
Other rules in Marin County
California rules heatmap·Compare Marin County to another location·View the California fence regulations overview
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