ADUs are allowed in TempeTypes:DetachedInternal
Types:DetachedInternal
Accessory Dwelling Unit (ADU) Rules for Tempe, AZ
Is your property eligible for an ADU?
# of Properties
44,394
Owner-occupied
59%
Zoning districts
31
Avg Home Value
$610,134
Median Lot Size
0.17 acres
Avg Income
$102,770
Residential Types:
44,394 housing units
2-3 Family
1%
Apts (4+ units)
2%
Other
98%
Zoning Districts:
50,609 parcels · 31 districts
R1-6
40%(20,441)
R-2
9%(4,708)
R1-7
9%(4,682)
R1-4
7%(3,754)
Other
34%(17,024)
ADU Rules
What can you build in Tempe, AZ?
Tempe, AZ follows state and local rules for Accessory Dwelling Units. Here is a concise overview of the local rules.
Eligibility
- –Internal / Attached ADU: By Right
- –Detached ADU: By Right
Interior / Attached ADU Size Limits
- –Maximum size of 1,000 sq ft on lots under 1 acre; 2,000 sq ft on lots at least 1 acre
- –Maximum size of 75% of the main residence’s interior habitable floor area
Detached ADU Size Limits
- –Maximum size is the lesser of 1,000 sq ft (or 2,000 sq ft on lots 1 acre or larger) and 75% of the main residence’s interior habitable floor area.
Max Units
- –Under 1 acre: max 2 ADUs per lot (1 attached + 1 detached).
- –1 acre or more: base 2 ADUs (1 attached + 1 detached); up to 3 total if at least one is deed-restricted affordable.
- –ADUs permitted only with single-family dwelling; duplex/triplex/fourplex or other multifamily principal structures not permitted; townhouses not eligible.
Owner Occupancy
- –There is no owner-occupancy requirement for ADUs.
Parking
- –0 spaces/ADU; owner may provide additional onsite parking. If ADU removes or modifies main residence parking, those spaces must be replaced in a location approved by the Community Development Director; ADUs are excluded from multi-family parking regulations.
Rental Restrictions
- –Restricted-affordable ADU on lots ≥1 acre: rent limited to households ≤80% AMI; must be deed-restricted with annual reporting; violations may incur civil sanctions/forfeiture
ADU State Law
What can you build in Arizona?
- –ADUs must be allowed as a permitted use wherever single-family dwellings are allowed.
- –Must allow at least 2 ADUs per lot (1 attached + 1 detached). A third detached ADU must be allowed if the lot is ≥ 1 acre and one ADU is restricted-affordable (≤ 80% Area Median Income).
- –ADU rules cannot be more restrictive than single-family rules in the same zoning area for height, setbacks, lot size, lot coverage, and building frontage; and side/rear setbacks cannot exceed 5 feet.
- –The city cannot require additional parking (or fees in lieu of parking).
- –The city cannot prohibit separately leased long-term rentals (≥ 90 days or month-to-month) for either the primary home or the ADU; local short-term rental rules may still apply.
- –The city cannot require the ADU to match exterior design, roof pitch, or finishing materials of the primary home.
- –The city cannot require public street improvements as a condition of allowing an ADU, except to repair or reconstruct a street disturbed by ADU construction.
- –The city cannot require a restrictive covenant as a condition of approving an ADU.
- –ADUs cannot be built over a public utility easement without written utility consent; building, fire, and health codes still apply, but the city cannot require commercial code or sprinklers solely because it is an ADU.
- –Private restrictions may still apply (HOAs, deed restrictions, and other private covenants between parties).
- –Backstop rule: If the municipality failed to adopt the required ADU regulations by January 1, 2025, ADUs are allowed on residential lots in that municipality without limits.
- –In municipalities with population ≤ 75,000, in unincorporated county areas, and on the statute's exempt lands (tribal; defined military vicinity; defined airport vicinity with >65 dB), there is no state ADU override. ADUs depend on local rules.
- –Private deed restrictions and HOA covenants may still limit ADUs, and the statute does not eliminate those private covenants (it mainly limits what a municipality can require or condition).
What's allowed on your lot?
These are the municipality-wide rules. What's allowed on a specific property also depends on state laws, setbacks, floor area ratio, lot coverage, environmental constraints, topography, and other property-specific factors. Search your address on FutureLot to see what's allowed on your property.
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ADU rules in other Arizona municipalities
Rules change at the town line. Check the municipality your property is actually in.
Maricopa County