ADU Rules: Rialto vs San Bernardino
How do adu rules rules compare between Rialto, CA and San Bernardino, CA?
Rialto and San Bernardino have similar restriction levels.
Rialto, CA
San Bernardino County
Rialto allows ADUs on single-family and multifamily lots under California Government Code §66314 (formerly §65852.2), with local zoning standards in Rialto Municipal Code Title 18 (Zoning). State law preempts most restrictive local provisions: a detached ADU up to 1,200 sq ft and a JADU up to 500 sq ft are allowed by right on a single-family lot, plus the city must permit at least one ADU and one JADU per single-family parcel.
View full Rialto rules →San Bernardino, CA
San Bernardino County
San Bernardino permits ADUs on single-family and multi-family lots under CA Gov Code 65852.2. Detached ADUs up to 1,200 sq ft and JADUs up to 500 sq ft are ministerially approved.
View full San Bernardino rules →Key Facts Comparison
| Fact | Rialto | San Bernardino |
|---|---|---|
| Governing law | Cal. Gov. Code §66314 (state ADU statute) + Rialto Municipal Code Title 18 (Zoning) | - |
| Max ADU size (state floor) | 850 sq ft studio/1-BR; 1,000 sq ft 2+ BR; up to 1,200 sq ft allowed | - |
| Min setback | 4 ft side/rear (state preemption) | - |
| Approval timeline | 60 days ministerial review (Gov. Code §66317) | - |
| Permit office | Rialto Building & Safety, 150 S Palm Ave, (909) 820-2505 | - |
| Legal authority | - | CA Gov Code 65852.2 statewide ADU mandate |
| Standard ADU | - | Up to 1,200 sq ft detached, 850 to 1,000 sq ft for attached |
| JADU | - | Up to 500 sq ft inside existing home with owner occupancy |
| Approval | - | Ministerial, 60-day review, no discretionary hearing |
| Parking | - | No parking required within 1/2 mile of transit |
Highlighted rows indicate differences between cities.
Rialto FAQ
Can Rialto deny my ADU if I meet state standards?
No. State law requires ministerial (non-discretionary) approval if your ADU meets the objective standards in Gov. Code §66314 — Rialto cannot impose a public hearing or design review on a code-compliant ADU.
Do I need to live on the property to build an ADU?
No owner-occupancy is required for an ADU permitted between Jan 1, 2020 and Jan 1, 2025 under Gov. Code §66314(a)(6). JADUs always require owner-occupancy of either the main house or the JADU under Gov. Code §66333.
San Bernardino FAQ
Does San Bernardino approve ADUs over the counter?
Yes. State law requires ministerial approval within 60 days of a complete application, with no discretionary hearings or subjective design review.
Do I have to live on the property to rent my ADU?
Owner occupancy is required for Junior ADUs. Standard ADUs permitted after 2020 are not subject to owner-occupancy rules until state law changes.
Can I rent my ADU on Airbnb?
State law generally requires ADU rentals be 30 days or longer, so short-term rental use is typically prohibited.
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