ADU Impact Fees: Gilbert vs Tempe
How do adu impact fees rules compare between Gilbert, AZ and Tempe, AZ?
Gilbert and Tempe have similar restriction levels.
Gilbert, AZ
Maricopa County
Gilbert charges development impact fees on new ADUs under ARS 9-463.05, but HB 2720 caps ADU impact fees in cities over 75,000 at no more than 50 percent of single-family detached rates in each category. Water and sewer capacity fees apply where a new meter is installed; shared utilities avoid those charges.
View full Gilbert rules →Tempe, AZ
Maricopa County
Tempe does not impose a dedicated ADU impact fee. Standard building, plumbing, mechanical, and electrical permit fees through Tempe Community Development apply based on construction valuation. Water and sewer development fees apply only when a new utility connection is installed. Arizona HB 2720 (ARS 9-461.18) limits fees that would effectively prohibit ADU construction.
View full Tempe rules →Key Facts Comparison
| Fact | Gilbert | Tempe |
|---|---|---|
| Fee Authority | ARS §9-463.05 | ARS 9-463.05 |
| ADU Cap | 50% of single-family rate | - |
| Typical Total | $4,000-$9,000 | - |
| Permit Fee | $600-$1,800 typical | - |
| Dedicated ADU Impact Fee | - | None |
| State Cap | - | ARS 9-461.18 limits punitive fees |
| Utility Fees | - | Only if new meter or connection |
| Permit Fee Basis | - | Construction valuation |
Highlighted rows indicate differences between cities.
Gilbert FAQ
How much are ADU impact fees in Gilbert?
Total impact fees typically run $4,000-$9,000 for a residential ADU depending on lot size and whether a separate water meter is required. ARS 9-461.18 caps ADU charges at 50 percent of single-family rates in each category.
Can I avoid water and sewer capacity fees by sharing utilities?
Yes in most cases. ADUs that connect to the primary dwelling's existing water and sewer service typically avoid separate capacity fees. Confirm with Gilbert Development Services and Water Resources during plan review.
Tempe FAQ
How much are impact fees for a Tempe ADU?
Tempe does not charge a dedicated ADU impact fee. You pay standard building, plumbing, mechanical, and electrical permit fees based on construction valuation, plus water and sewer development fees only if a new meter or service is installed. Request a written fee estimate from Tempe Community Development before submittal.
Can Tempe charge me the full single-family impact fee for an ADU?
No. Under ARS 9-461.18 (HB 2720), fees that would effectively prohibit ADU construction are barred. Tempe applies its standard transportation, parks, and public safety impact fees to new principal-unit construction, not as a duplicate charge on accessory dwelling units sharing the existing lot.
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