ADU Impact Fees: Ontario vs Rialto
How do adu impact fees rules compare between Ontario, CA and Rialto, CA?
Ontario, CA
San Bernardino County
No data available yet for Ontario.
Rialto, CA
San Bernardino County
ADUs under 750 sq ft are exempt from all impact fees in Rialto by force of state law (Cal. Gov. Code §66314(f)(3)). ADUs 750 sq ft or larger may be charged impact fees only proportionally to the primary dwelling's square footage. School-district fees are separately governed.
View full Rialto rules →Key Facts Comparison
| Fact | Ontario | Rialto |
|---|---|---|
| Impact fee exemption | - | ADUs under 750 sq ft — zero impact fees (Cal. Gov. Code §66314(f)(3)(A)) |
| Larger ADUs (750+ sq ft) | - | Proportional fees only, based on ratio to primary dwelling |
| School fees | - | Not preempted; may apply over 500 sq ft (Ed. Code §17620) |
| Building permit fees | - | Cost-of-service charges still apply |
| Enforcement | - | HCD complaint under Gov. Code §66317.7 |
Highlighted rows indicate differences between cities.
Ontario FAQ
No FAQs available.
Rialto FAQ
Will I pay impact fees on my 600 sq ft ADU?
No. State law (Cal. Gov. Code §66314(f)(3)(A)) prohibits any impact fees on ADUs under 750 sq ft. Building permit and plan-check fees still apply, but park, traffic, and sewer-capacity impact fees are exempt.
What if Rialto charges me an impact fee on a small ADU?
It's preempted. Request a written fee breakdown and cite Gov. Code §66314(f)(3)(A). Unresolved disputes can be escalated to California HCD's Housing Accountability Unit.
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