Rialto, CA Accessory Structures: Garage Conversions (2026)
Garage conversion rules in Rialto, CA, sometimes called garage-to-ADU or accessory living unit conversions, govern permits, ceiling height, egress, and parking replacement.
Key Facts
- Approval
- Ministerial; conversions keep existing setbacks
- Garage door
- Must be removed and replaced with matching windows/doors
- Replacement parking
- Not required when garage or carport is converted
- Allowed expansion
- Up to 150 sq ft for ingress and egress (Gov. Code 66323)
- Pre-2020 units
- Legalization path under AB 2533 / Gov. Code 66332
- Impact fees
- No impact fees or connection charges for pre-2020 legalizations, with limited exceptions
Summary
Rialto ministerially approves conversion of an existing, legally permitted garage into an ADU with no new setbacks and no replacement parking, but the garage door must be replaced with windows or doors matching the home. Unpermitted units built before 2020 can be legalized under AB 2533.
Unpermitted Accessory Dwelling Units (ADU) or Junior Accessory Dwelling Units (JADU) constructed before January 1, 2020 may request to apply the provisions of Government Code 66332. Before making the request to the city and submitting an application for a permit, the homeowner may obtain a confidential third-party code inspection from a licensed contractor to determine the unit's existing condition or potential scope of building improvements before submitting an application for a permit. The confidential third-party code inspection is a resource for the homeowner and is not reviewed or accepted by the city. To apply the provisions of Government Code 66332 the applicant must provide clear evidence that the ADU or JADU was constructed before January 1, 2020 and that the use was a ADU or JADU. ... Once it's determined that the ADU was constructed before January 1, 2020, the second step is to ensure that the ADU does not violate the provisions listed under the Health and Safety Code for a Substandard Building. To verify, the applicant must obtain Special Inspection Investigation Permit, and the city inspector will inspect the unit under the provisions of the Health and Safety Code for a Substandard Building.
Full Breakdown
Rialto Municipal Code Section 18.10.070(K) allows an existing, legally permitted attached or detached structure, including a garage, to be converted to an ADU with no setback beyond what existed before conversion; the garage door must be removed and replaced with windows, doors, or design treatments consistent with the home's architecture. Replacement parking is not required when a garage, carport, or covered parking structure is converted or demolished for an ADU (subsection N). Government Code Section 66323 permits expanding up to 150 square feet beyond existing dimensions for ingress and egress. Under AB 2533 (Government Code 66332), unpermitted ADUs built before January 1, 2020 may be legalized through Rialto's Special Inspection Investigation Permit process after substandard-building review.
Violations & Fines
Unpermitted garage conversions are subject to code enforcement, but for units completed before January 1, 2020 the city may not penalize an applicant seeking legalization and must approve permits needed to correct health and safety violations.
Frequently Asked Questions
Can I legalize an old unpermitted garage conversion in Rialto?
Do I have to replace the parking lost when converting my Rialto garage?
Can I get a private inspection before applying to legalize a unit?
Sources & Official References
Other rules in Rialto
California rules heatmap·Compare Rialto to another location·View the California accessory structures overview
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Garage Conversions in Nearby Cities
How other cities in San Bernardino County handle garage conversions.