ADU Impact Fees: Hesperia vs Rialto
How do adu impact fees rules compare between Hesperia, CA and Rialto, CA?
Hesperia and Rialto have similar restriction levels.
Hesperia, CA
San Bernardino County
California Gov. Code 66315 prohibits Hesperia from imposing impact fees on ADUs under 750 sq ft. Larger ADUs may only be charged fees proportional to the primary dwelling's square footage. School fees and Mojave Water Agency capacity fees may still apply.
View full Hesperia rules →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 | Hesperia | Rialto |
|---|---|---|
| ADUs under 750 sq ft | No city impact fees | - |
| ADUs 750+ sq ft | Proportional fees only | - |
| Authority | Cal. Gov. Code 66315 | - |
| Water/Sewer Connection | Mojave Water Agency / Victor Valley WRA | - |
| School Fees | May apply for ADUs over 500 sq ft (Ed. Code 17620) | - |
| 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.
Hesperia FAQ
Does Hesperia charge impact fees on a 600 sq ft ADU?
No. California Gov. Code 66315 prohibits any city impact fee on ADUs under 750 sq ft. Building permit fees and water/sewer connection charges may still apply at actual cost.
What fees apply to a 1,000 sq ft ADU in Hesperia?
Building permit and plan check fees apply, plus impact fees proportional to the ADU's share of the primary dwelling's square footage. School fees from Hesperia Unified may apply since the ADU exceeds 500 sq ft, and Mojave Water Agency capacity fees may also apply.
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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