Garage Conversions: Ontario vs Rialto
How do garage conversions rules compare between Ontario, CA and Rialto, CA?
Ontario and Rialto have similar restriction levels.
Ontario, CA
San Bernardino County
Ontario allows garage-to-ADU conversions under Gov Code 65852.2 with no replacement parking required. Non-ADU conversions to living space still need a building permit and must replace covered parking.
View full Ontario rules →Rialto, CA
San Bernardino County
Converting a garage into living space in Rialto is governed by Rialto Municipal Code Title 18 (Zoning) and Title 15 (Buildings). Most garage conversions are processed as ADUs (accessory dwelling units) under California Government Code §65852.2 (state ADU law), which preempts most local restrictions and requires Rialto to ministerially approve a qualifying garage-to-ADU conversion.
View full Rialto rules →Key Facts Comparison
| Fact | Ontario | Rialto |
|---|---|---|
| ADU conversion | Gov Code 65852.2 | - |
| Replacement parking | Not required for ADU | - |
| Permit type | Building permit required | - |
| Egress | Bedroom window or door | - |
| Non-ADU conversion | Parking must be replaced | - |
| State ADU preemption | - | Cal. Gov. Code §65852.2 — ministerial approval, no parking replacement |
| Local code | - | RMC Title 18 (Zoning) + Title 15 (CBC adoption) |
| Permit required | - | Yes — building permit and ADU/zoning clearance |
| Enforcement | - | Rialto Community Compliance |
Highlighted rows indicate differences between cities.
Ontario FAQ
Can Ontario make me add another parking space when I convert my garage to an ADU?
No. State law prohibits requiring replacement parking when a garage is converted to an ADU, even if the original garage provided the home's only covered parking.
Do I need a permit to turn my garage into a home gym?
Yes. Any conversion of garage space to living space requires a building permit, insulation, egress, and often a change-of-use review even if it is not an ADU.
Rialto FAQ
Can Rialto deny my garage-to-ADU conversion?
Under Cal. Gov. Code §65852.2, qualifying garage-to-ADU conversions get ministerial (non-discretionary) approval. Rialto can require compliance with building, health, and safety codes but cannot impose discretionary review or require parking replacement.
Do I need to replace the parking I lose?
Not if it's a state-law ADU conversion. State law specifically prohibits requiring replacement parking when an existing garage is converted to an ADU.
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