Retaining Walls: Antioch vs Brentwood
How do retaining walls rules compare between Antioch, CA and Brentwood, CA?
Antioch and Brentwood have similar restriction levels.
Antioch, CA
Contra Costa County
Retaining walls up to 4 feet in height (measured from bottom of footing to top of wall) without surcharge typically do not require a building permit in Antioch. Walls taller than 4 feet, or supporting a surcharge (driveway, pool, slope), require engineered plans and a permit.
View full Antioch rules →Brentwood, CA
Contra Costa County
Retaining walls in Brentwood up to 4 feet in height measured from the bottom of the footing to the top of the wall generally do not require a building permit if they do not support a surcharge (driveway, slope, or structure). Walls over 4 feet or supporting a surcharge require a building permit with engineered drawings.
View full Brentwood rules →Key Facts Comparison
| Fact | Antioch | Brentwood |
|---|---|---|
| Permit Threshold | Over 4 ft = permit required | - |
| Engineering | Required over 4 ft or with surcharge | Licensed CA engineer stamp |
| Surcharge Examples | Driveway, pool, structure loads | - |
| Drainage | Weep holes/drain pipe required | Required behind wall |
| Counting | Separate from fence height | - |
| No-permit threshold | - | Up to 4 ft, no surcharge |
| Permit required | - | >4 ft or any surcharge |
| Grading trigger | - | >50 cu yd earthwork |
Highlighted rows indicate differences between cities.
Antioch FAQ
Does a 3-foot retaining wall need a permit?
Generally no, as long as it supports no surcharge (such as a driveway or pool above it) and complies with zoning. However, drainage and setback requirements still apply.
Can I put a fence on top of my retaining wall?
Yes, but combined height may count for fence height limits depending on configuration. Walls over 30 inches adjacent to walking surfaces may also require a guardrail per California Building Code.
Brentwood FAQ
Do I need a permit for a 3-foot garden wall?
Not if it's a freestanding decorative wall under 4 feet with no soil or slope pressing against it. If it retains any slope or drive, even a 2-foot wall may require a permit and engineering.
Can I build a retaining wall on the property line?
Generally yes, subject to setbacks and the Good Neighbor Fence Act for any boundary fence on top. Walls supporting a neighbor's soil or structure require a written agreement or easement, and the neighbor must be notified.
Compare other topics
See how Antioch and Brentwood compare on other ordinance categories.
Want to add a third city?
Use our full comparison tool to compare up to three cities.
Open Comparison Tool