ADU Impact Fees: Glendale vs Phoenix
How do adu impact fees rules compare between Glendale, AZ and Phoenix, AZ?
Phoenix has fewer restrictions than Glendale.
Glendale, AZ
Maricopa County
Ariz. Rev. Stat. section 9-461.18 prohibits Glendale from imposing street impact fees on accessory dwelling units and limits other fees that could undermine the state by-right mandate. Standard building permit and plan review fees apply, scaled to construction valuation. Water and sewer development fees apply because Glendale requires a separate water meter and tap for every ADU, generating new connection charges that ordinary internal conversions in other cities avoid.
View full Glendale 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 | Glendale | Phoenix |
|---|---|---|
| Street Impact Fee | Not applied (state preempted) | - |
| State Cap | ARS 9-461.18 limits excessive ADU fees | - |
| Permit Fee Basis | Construction valuation | - |
| Water Meter Fee | Required (separate meter per ADU) | - |
| Water Tap | New tap to main required | - |
| Reference Document | Glendale ADU Update Mar 2025 | - |
| Fee Authority | - | ARS §9-463.05 |
| ADU Cap | - | 50% of single-family rate |
| Typical Total | - | $4,000-$8,000 |
| Permit Fee | - | $500-$1,500 typical |
Highlighted rows indicate differences between cities.
Glendale FAQ
Does Glendale charge an ADU impact fee?
Streets impact fees do not apply to ADUs because state law (Ariz. Rev. Stat. 9-461.18) prohibits requiring street improvements. Glendale does charge standard building permit fees scaled to construction valuation, and unlike many cities, requires a separate water meter and new tap for every ADU, which generates meter and connection fees.
Why is Glendale's ADU water fee higher than other Arizona cities?
Glendale uniquely requires every ADU to have its own city water meter with a new tap to the water main in the street or right-of-way. Most Arizona cities permit ADUs to share the primary dwelling's meter and service, avoiding new connection fees. Plan for separate water meter and tap charges in your Glendale ADU budget.
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.
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