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Tempe Architect — Additions, ADUs, Infill & Multifamily

Tempe is a built-out city, which makes it an addition, ADU and infill market rather than a greenfield one. It also has some of the most permissive accessory dwelling unit rules in the Valley following Arizona's 2024 ADU statute — worth understanding before you assume a casita is out of reach.

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The short answer

In Tempe the two most useful facts are that ADUs are now permitted wherever single-family dwellings are allowed, with no parking requirement, and that single-family lot coverage caps at 45% of net site area. Between those two numbers sits most of what is possible on a Tempe residential lot.

The Big One

Accessory dwelling units in Tempe

Arizona HB 2720, signed 21 May 2024 and codified at A.R.S. §9-416.18, requires municipalities of 75,000 or more residents to permit ADUs wherever single-family dwellings are allowed. Tempe amended its ordinance in response. The result is notably permissive:

Size

  • Lots under 1 acre: max 75% of the main dwelling's interior habitable floor area or 1,000 SF — whichever is less.
  • Lots 1 acre or more: max 75% or 2,000 SF — whichever is less.

Number

  • One attached + one detached ADU per single-family lot.
  • On lots of 1 acre or more, an additional ADU is allowed if at least one is income-restricted affordable at an 80% AMI cap.

Setbacks, height and parking

  • Minimum 5 ft rear, side and street-side — unless the district's setback is less. Front yard per the district's single-family requirement.
  • Height per zoning district. Two-storey ADUs require a Use Permit (Board of Adjustment decision dated 17 December 2025 — recent enough that older guidance is stale).
  • No parking required — state law prohibits the requirement.
  • Owner occupancy on site required only where the ADU is licensed as a short-term rental and was constructed on or after 20 December 2024.

Source: City of Tempe — Accessory Dwelling Units

Zoning Reference

Tempe single-family standards

DistrictMin lot area / DU
R1-1515,000 SF
R1-1010,000 SF
R1-88,000 SF
R1-77,000 SF
R1-66,000 SF
  • Maximum lot coverage: 45% of net site area, consistent across single-family districts.
  • Front setback: 20 ft (R1-8 through R1-4) up to 35 ft (R1-15).
  • Side setback: 5 ft (R1-6) up to 20 ft depending on district.
  • Rear setback: 15 ft to 35 ft depending on district.
  • Maximum building height: confirm against the codified table. We do not quote a figure here because the value in the widely circulated adopted PDF is not reliable.

Figures above derive from the adopted Zoning and Development Code Table 4-202A. Tempe has proposed code changes in progress, and the December 2025 ADU activity shows the code is actively in flux — E-Project confirms current standards against the codified version for every Tempe project.

Process

Who reviews what in Tempe

Building Safety Division

Residential plan review — single-family, ADU, duplex, townhouse. Part of the Community Development Department. Submittals run through the Tempe Citizen Access portal.

Planning Division

Entitlements: use permits, variances, development plans and land division approvals, with decisions through the Development Review Commission, Board of Adjustment and a Hearing Officer. A preliminary site plan review step exists.

Building Development Plan Review

Tempe's streamlining program combining entitlements with building permit applications — existing buildings only. Covers tenant improvements with minor exterior modifications, commercial additions under 5,000 SF, adaptive reuse, parking lot improvements and accessory buildings. Not new single-family or residential additions.

Tempe does not publish a verifiable residential plan review turnaround figure. Treat any number you are quoted for Tempe review duration as unsourced until confirmed with the permit center. One verified expedited path exists: SolarAPP+ for eligible single-family residential PV, same-day — solar only.

Relevant Experience

Infill, townhome and multifamily work

Tempe's residential growth is infill and attached housing, which is where a large part of E-Project's portfolio sits: The Crossing at Gila Springs (60 units, 2020), Villa Rialto (42 units, 2016), Nido 18 (18 units, 2021), Bella Vita (18 units, 2016), The Luxe (10 units, 2019), Miller Square (10 units, 2019), Country Club Townhomes (7 units, in construction), Earl 6 (6 townhomes), Wilshire Place (5 units, 2020) and Turney Court (4 units, 2020) — plus subdivision work at Alexanor, Paradise Lane and Pinchot Square.

See townhome & condominium work

Services in Tempe

Frequently Asked Questions

Can I build an ADU or casita in Tempe?

Yes. Arizona HB 2720, signed May 2024 and codified at A.R.S. section 9-416.18, requires municipalities of 75,000 or more residents to permit accessory dwelling units wherever single-family dwellings are allowed, and Tempe amended its ordinance in response. On lots under one acre, an ADU may be up to 75 percent of the main dwelling's interior habitable floor area or 1,000 square feet, whichever is less. On lots of one acre or more, up to 75 percent or 2,000 square feet, whichever is less. One attached plus one detached ADU is allowed per single-family lot.

What are the ADU setbacks and parking requirements in Tempe?

Minimum 5 feet rear, side and street-side, unless the district's setback is less; the front yard follows the district's single-family requirement. No parking is required — state law prohibits municipalities from requiring it. Height follows the zoning district, but note that as of a Board of Adjustment decision dated December 17, 2025, two-storey ADUs require a Use Permit. Owner occupancy on site is required only if the ADU is licensed as a short-term rental and was constructed on or after December 20, 2024.

How long does residential plan review take in Tempe?

Tempe references a target turn-around times resource but does not publish a figure that can be independently verified, so any number quoted for Tempe review duration should be treated as unsourced. Confirm directly with the permit center. One verified expedited path exists: Tempe accepts SolarAPP+ for eligible single-family residential photovoltaic permits, enabling same-day approval — but that is solar only.

What are the lot coverage and setback rules for Tempe single-family?

Per the adopted Zoning and Development Code Table 4-202A, maximum lot coverage is 45 percent of net site area, consistent across the single-family districts. Minimum lot area per dwelling unit runs from 15,000 square feet in R1-15 down to 6,000 square feet in R1-6. Front setbacks range from 20 feet in R1-8 through R1-4 up to 35 feet in R1-15; side setbacks from 5 feet in R1-6 up to 20 feet; rear setbacks from 15 to 35 feet depending on district. Maximum building height should be confirmed directly against the codified table rather than assumed.

Who reviews multifamily and townhome projects in Tempe?

The Community Development Department. Building Safety handles residential plan review including single-family, ADU, duplex and townhouse; the Planning Division handles entitlements — use permits, variances, development plans and land division approvals — through bodies including the Development Review Commission, Board of Adjustment and a Hearing Officer. Applications submit through the Tempe Citizen Access portal, and a preliminary site plan review step exists. The precise sequence for a given project is worth confirming with Planning at the outset.

Thinking about a casita, an addition or an infill project in Tempe?

Tempe's ADU rules changed recently and are more permissive than most people assume. Let's check what your lot allows.

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Or call 480-626-8648 · info@e-projectinternational.com