Retaining Walls: Castro Valley vs San Leandro
How do retaining walls rules compare between Castro Valley, CA and San Leandro, CA?
San Leandro has fewer restrictions than Castro Valley.
Castro Valley, CA
Alameda County
Retaining walls over 4 feet in height (measured from bottom of footing to top) require a building permit and engineered plans in unincorporated Alameda County under the California Building Code.
View full Castro Valley rules →San Leandro, CA
Alameda County
Under the 2022 California Building Code as adopted by San Leandro in SLMC Title 7 Chapter 7-5 (Building Code), a building permit is required for any retaining wall over 4 feet measured from the bottom of the footing to the top of the wall, or for any wall of any height that supports a surcharge (such as a slope or driveway above the wall).
View full San Leandro rules →Key Facts Comparison
| Fact | Castro Valley | San Leandro |
|---|---|---|
| Permit threshold | Over 4 feet | - |
| Engineering | Required for permitted walls | - |
| Surcharge walls | Permit required any height | - |
| Hillside areas | Soils report may apply | - |
| Code Section | - | SLMC 7-5 adopting CBC 105.2 |
| Permit Threshold | - | Over 4 ft (footing to top) OR any wall with surcharge |
| Engineering Required | - | Walls over 6 ft total height |
| Department | - | Building & Safety Division |
| Contact | - | (510) 577-3405 |
Highlighted rows indicate differences between cities.
Castro Valley FAQ
Do I need a permit for a 3-foot garden wall?
Generally no, unless it supports a surcharge such as a driveway or slope above, but always verify with the county building department.
Can I DIY a retaining wall?
Non-permitted walls under 4 feet may be DIY, but permitted walls require engineered plans and licensed installation is strongly recommended.
San Leandro FAQ
Do I need a permit for a retaining wall in San Leandro?
Yes if the wall is more than 4 feet from the bottom of the footing to the top of the wall, OR if it retains a slope, driveway, pool, or any other surcharge regardless of height. Walls 4 feet or less without a surcharge are exempt under CBC 105.2 as adopted in SLMC 7-5.
Can I build a retaining wall on my property line?
Yes, but a wall on or near a property line still needs to meet the zoning rules in SLMC Article 6 for combined wall-plus-fence height (typically 6 feet rear/side, 42 inches front), and a survey is recommended. Walls over 4 feet need a permit even on a property line.
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