Retaining Walls: Ontario vs Rialto
How do retaining walls rules compare between Ontario, CA and Rialto, CA?
Rialto 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 →Rialto, CA
San Bernardino County
Retaining walls in Rialto are governed by California Building Code §105.2 (adopted via Rialto Code Title 15) and zoning standards in §18.61.170. Any retaining wall over 4 feet measured from bottom of footing to top of wall, or any wall supporting a surcharge, requires a building permit.
View full Rialto rules →Key Facts Comparison
| Fact | Ontario | Rialto |
|---|---|---|
| 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 ft (footing to top) or any wall with surcharge |
| Code Authority | - | CBC §105.2 (CCR Title 24) via Rialto Code Title 15 |
| Zoning | - | Rialto Code §18.61.170 height standards |
| Building & Safety | - | 150 S Palm Ave; 909-820-2505 |
| Boundary Walls | - | Cal. Civ. Code §841 cost-sharing applies |
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.
Rialto FAQ
Do I need a permit for a 3-foot retaining wall in Rialto?
Generally no, if it does not support a surcharge (vehicle load or sloped soil). California Building Code §105.2 exempts walls 4 feet or less without surcharge.
What if my retaining wall holds up a driveway?
Any retaining wall supporting a surcharge (including a driveway or parked vehicle load) requires a building permit per CBC §105.2, regardless of height. Contact Rialto Building & Safety at 909-820-2505.
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