Retaining Walls: Ontario vs San Bernardino
How do retaining walls rules compare between Ontario, CA and San Bernardino, CA?
San Bernardino has fewer restrictions than Ontario.
Ontario, CA
San Bernardino County
Ontario requires a permit for any retaining wall over 4 feet (footing to top) or carrying a surcharge such as a slope or driveway. Engineered plans by a licensed California civil or structural engineer are required.
View full Ontario rules →San Bernardino, CA
San Bernardino County
Retaining walls over four feet from the bottom of the footing, or any wall supporting a surcharge, require a building permit and engineered plans under the California Building Code.
View full San Bernardino rules →Key Facts Comparison
| Fact | Ontario | San Bernardino |
|---|---|---|
| No Permit | Up to 4 feet unsurcharged | - |
| Permit Required | Over 4 feet or surcharged | - |
| Plans | Licensed engineer required | - |
| Drainage | Cannot flow to neighbor | - |
| Measurement | Bottom of footing to top | - |
| Permit Threshold | - | Over 4 feet or with surcharge |
| Engineer | - | Licensed CA engineer stamp |
| Seismic Concern | - | Near San Andreas and San Jacinto faults |
| Building and Safety | - | 909-384-5065 |
Highlighted rows indicate differences between cities.
Ontario FAQ
Does a 3-foot retaining wall in Ontario need a permit?
Usually no if it is unsurcharged. If a slope, driveway, or pool loads the top of the wall, it is surcharged and does need a permit.
Who is liable if the wall fails?
The property owner. Using an engineer and permit creates a defensible record. Unpermitted walls expose you to liability for damage downhill and next door.
San Bernardino FAQ
Do I need an engineer for a three-foot wall?
Generally no if it is less than four feet from the footing and carries no surcharge; taller or loaded walls require engineered plans.
What is a surcharge?
Any load above the wall such as a sloped yard, driveway, or structure that adds pressure; walls with a surcharge need a permit regardless of height.
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