Rules by jurisdiction
| Where | Permit needed when | Also note | Source |
|---|---|---|---|
| Walnut Creek | Over 4 ft from bottom of footing to top of wall; any surcharge; load from or onto a building; supports a solid fence portion over 3 ft | Site development permit over 4 ft or with surcharge. Design by a licensed architect or civil/structural engineer. Soils report for tiered walls and undrained designs. | City page |
| Unincorporated County: Alamo, Blackhawk, Diablo | Over 3 ft from top of footing to top of wall; also when the ground below slopes down more than 1:10, or the wall supports a surcharge or a slope steeper than 1:2 | A wall on fill needs a grading permit. | County PDF |
| Lafayette | City zoning plan check first; Contra Costa County Building Inspection handles plan check and inspections | Ask at the zoning check which height threshold applies. Grading threshold 50 cu yd. | City page · County grading |
| Danville | Supports more than 3 ft of soil; or surcharge from vehicles, nearby structures, a sloping site or an uphill tier | Separate grading permit page. | Town page · grading |
| Orinda | Confirm with the City of Orinda | City runs its own drainage/grading permit process; County lists a 50 cu yd grading threshold. | City PDF · County grading |
| Moraga | Confirm with the Town of Moraga | 50 cu yd grading threshold per the County. | Town FAQ |
| Pleasant Hill, Concord, Clayton | Check with the city building division | Not covered on this site yet. | — |
How height is measured
Walnut Creek
Bottom of footing → top of wall. A wall showing 3 ft above grade on a 1-ft-deep footing is 4 ft.
County
Top of footing → top of wall, with slope conditions.
Danville
Height of soil retained, lower grade → upper grade.
Walnut Creek’s line matches the exemption in the California Residential Code (section R105.2), which most local codes start from (Walnut Creek exempt work list).
Close to a threshold? A contractor can tell you how your wall will be measured and who handles the permit.
When you need an engineer or a soils report
- Any permitted wall in Walnut Creek: design by a licensed architect or a registered civil or structural engineer (City).
- Tiered walls, undrained designs, weak soils or Alquist-Priolo zones in Walnut Creek: a soils report by a civil or geotechnical engineer.
- Walls holding up a driveway, house, slope or another wall: surcharge, so engineering in every jurisdiction above.
- Repairs involving tie-backs or anchors: engineered and permitted.
Grading permits
A wall that needs a big cut or fill can need a grading permit too. The County’s thresholds: excavations deeper than 5 ft or over 200 cubic yards; fill supporting a structure, deeper than 3 ft or over 200 cubic yards, with 50 cubic yards in Lafayette, Moraga and Orinda (Contra Costa County). Walnut Creek also issues site development permits for grading-type work.
What the permit process involves
Design
Site plan, wall elevations and sections showing footing, reinforcement and drainage, stamped by the designer or engineer.
Soils report (when required)
A geotechnical engineer’s findings on soil strength and drainage.
Plan check
The city or County reviews; Lafayette starts with a city zoning check.
Inspections
Typically footing and reinforcement before the pour, drainage before backfill, and a final.
HOA approval
Many HOAs review walls separately, for example Blackhawk’s architectural review.
Before digging, call USA North 811 to mark buried utilities. Next: who to hire, what it costs, and hillside walls.
Common questions
Do you need a permit for a retaining wall in California?
Under the California Residential Code’s exemption list (R105.2), walls up to 4 feet from the bottom of the footing that don’t support a surcharge are exempt, but cities and counties set their own rules on top. Walnut Creek follows the 4-foot, bottom-of-footing line; the unincorporated County uses 3 feet from the top of the footing; Danville uses 3 feet of retained soil.
Does a retaining wall need an engineer?
For a permitted wall in Walnut Creek, yes: the design must come from a licensed architect or a registered civil or structural engineer, and tiered walls also need a soils report. Low, unloaded garden walls usually don’t.
Who gets the permit, me or the contractor?
Either can, but the contract should say who. Most homeowners have the contractor or designer handle drawings, engineering and the application. Ask before you sign.
Sources
- City of Walnut Creek: Retaining walls
- City of Walnut Creek: Work not requiring a permit
- City of Walnut Creek: Site development permits
- Contra Costa County: Retaining walls (PDF)
- Contra Costa County: Grading permits
- City of Lafayette: Building permits
- Town of Danville: Retaining wall permit
- Town of Danville: Grading permit
- City of Orinda: Drainage/grading permit process (PDF)
- Town of Moraga: Building permit FAQs
- Blackhawk HOA architectural review
- USA North 811
Checked October 2026. Rules and prices change; confirm with the agency or a contractor before you build.