ADU Impact Fees: Gilbert vs Phoenix
How do adu impact fees rules compare between Gilbert, AZ and Phoenix, AZ?
Gilbert and Phoenix 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 →Phoenix, AZ
Maricopa County
Phoenix charges modest development impact fees on ADUs under Arizona Revised Statutes Section 9-463.05. HB 2928 caps ADU impact fees in cities over 75,000 at 50 percent of single-family rates. Phoenix water and wastewater capacity charges apply where new meters are installed.
View full Phoenix rules →Key Facts Comparison
| Fact | Gilbert | Phoenix |
|---|---|---|
| Fee Authority | ARS §9-463.05 | ARS §9-463.05 |
| ADU Cap | 50% of single-family rate | 50% of single-family rate |
| Typical Total | $4,000-$9,000 | $4,000-$8,000 |
| Permit Fee | $600-$1,800 typical | $500-$1,500 typical |
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.
Phoenix FAQ
How much are ADU impact fees in Phoenix?
Total impact fees typically run $4,000-$8,000 for a residential ADU. Under HB 2928, Phoenix must charge ADUs at no more than 50 percent of single-family rates in each category (water, wastewater, parks, fire, police, library, streets).
Are Phoenix ADUs under 750 sq ft exempt from impact fees?
No automatic exemption like California. Arizona HB 2928 caps ADU fees at 50 percent of single-family rates but does not provide a size-based exemption. Phoenix charges proportional fees regardless of ADU size.
Compare other topics
See how Gilbert and Phoenix compare on other ordinance categories.
Want to add a third city?
Use our full comparison tool to compare up to three cities.
Open Comparison Tool