ADU Impact Fees: Phoenix vs Surprise
How do adu impact fees rules compare between Phoenix, AZ and Surprise, AZ?
Phoenix and Surprise have similar restriction levels.
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 →Surprise, AZ
Maricopa County
Under ARS § 9-463.05 and the ADU preemption at ARS § 9-461.18, Surprise cannot charge development impact fees on ADUs under 1,000 square feet, and fees on larger ADUs must be proportionate to the unit's actual demand on infrastructure. The Surprise Development Services Fee Schedule sets building permit and plan-check fees through the Community Development Department. Water and wastewater capacity fees apply only when a new tap is installed.
View full Surprise rules →Key Facts Comparison
| Fact | Phoenix | Surprise |
|---|---|---|
| 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 | - |
| State Exemption | - | ADUs < 1,000 sq ft exempt (ARS § 9-461.18) |
| Impact Fee Authority | - | ARS § 9-463.05 |
| Permit Fee Range | - | ~$500–$2,000 typical |
| Water/Sewer SDF | - | Only on new tap |
| Fee Schedule | - | Surprise Development Services |
Highlighted rows indicate differences between cities.
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.
Surprise FAQ
Are ADU impact fees waived in Surprise?
Yes for ADUs under 1,000 square feet. ARS § 9-461.18 prohibits Surprise from charging impact fees on small ADUs. Larger ADUs pay proportional fees based on the principal dwelling's square footage under ARS § 9-463.05.
What does an ADU permit cost in Surprise?
Building permit and plan-check fees typically total $500–$2,000 for a small ADU sharing the main house's utilities. New water/sewer tap System Development Fees add several thousand dollars. Check the Surprise Development Services Fee Schedule for current rates.
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