ADU Impact Fees: Gilbert vs Surprise
How do adu impact fees rules compare between Gilbert, AZ and Surprise, AZ?
Gilbert and Surprise 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 →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 | Gilbert | Surprise |
|---|---|---|
| Fee Authority | ARS §9-463.05 | - |
| ADU Cap | 50% of single-family rate | - |
| Typical Total | $4,000-$9,000 | - |
| Permit Fee | $600-$1,800 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.
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.
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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