Building an ADU (casita) in Scottsdale

What you can build in Scottsdale

Arizona's ADU law, ARS 9-461.18 (HB 2720, 2024), "applies to a municipality with a population of more than seventy-five thousand persons." Scottsdale adopted its ADU rules in Ordinance 4652 (November 2024) and amended them with Ordinance 4687 on Sept. 30, 2025, after HB 2928 shrank the airport areas where ADUs could be barred. The city says ADUs have been allowed since January 1, 2025. The rules are in Zoning Ordinance Sections 7.900 to 7.904; as of November 2026 the online code still showed the older airport wording, so the Ordinance 4687 text has the current version of that rule. See our Arizona ADU law page.

Scottsdale recognizes three types of ADU:

• One attached ADU per single-family lot.
• One detached ADU per single-family lot.
• On a lot of an acre or more, one more restricted-affordable detached ADU. It must be rented only to households earning up to 80% of area median income, at rents based on Arizona Department of Housing limits, can't be a short-term rental, and needs a recorded private deed restriction before any permit is issued.

An ADU must have its own sleeping, kitchen and sanitary facilities. It can only be built after the main home has its certificate of occupancy. Existing buildings, or part of one, can be converted if they meet the same rules. The city says any ADU that existed before the new rules is illegal until it is approved under them. [1][2][3][5][6][7]

ADU or guest house?

Scottsdale treats a guest house and an ADU as different uses. A guest house is a detached building for guests of the people living in the main home. It can't be rented separately, must share utilities with the main home, and all guest houses on a lot together can be up to half the main home's floor area. A guest house built after January 1, 2025 needs a recorded private deed restriction limiting it to guest house use before the permit is approved. It goes straight to building permits, with no administrative ADU review.

An ADU can be attached or detached, must have its own kitchen and separately metered utilities, and can be rented. The city says an existing guest house can become an ADU if the owner shows it meets the ADU rules and gets approval. See the city's guest house page. [1][3][8]

Size, height and setbacks

Size. Only one ADU on a lot can be as large as 75% of the main home's gross floor area or 1,000 square feet, whichever is less. Every other ADU on the same lot is limited to 500 square feet.

Height. An ADU can't be taller than the height allowed in its zoning district.

Setbacks. An attached ADU follows the setbacks for the main home. A detached ADU can't go in the required front yard (including the front yard on the longer street side of a corner lot) or in a required side yard. A detached ADU in the rear yard can be built 5 feet from a side or rear property line. Each ADU must be at least 10 feet from the main home and from any other ADU.

Other standards. Each ADU needs its own exterior entrance, a path to the street that doesn't go through the main home, its own address, and private outdoor space next to it of at least 5 feet deep and 50 square feet. The zoning district's other development standards still apply unless the ADU section says otherwise.

How this lines up with state law. ARS 9-461.18 requires cities to allow "at least one attached and one detached accessory dwelling unit as a permitted use" and "an accessory dwelling unit that is seventy-five percent of the gross floor area of the single-family dwelling ... or one thousand square feet, whichever is less." It bars rear or side setbacks for ADUs "that are more than five feet from the property line." Scottsdale's code lets only one ADU on a lot reach that size and caps every other ADU at 500 square feet; Ordinance 4652's recitals describe the state allowance as "a cumulative seventy-five percent," a word the statute itself doesn't use. The code also keeps detached ADUs out of required side yards. If your plan depends on a second ADU over 500 square feet or a detached ADU in a side yard, confirm with the One Stop Shop at 480-312-2500. [1][2][4][5][9]

Parking

Scottsdale doesn't require any added parking for an ADU. But its code says an ADU "shall not reduce or eliminate any required parking for the main single-family residential dwelling," and if the ADU removes required spaces (for example, in a garage conversion), they must be replaced on the same lot where the Zoning Administrator approves.

Arizona law says a city may not "require that a lot or parcel have additional parking to accommodate an accessory dwelling unit." If you plan to convert a garage or carport, ask the One Stop Shop how the replacement rule applies to your lot. See our garage conversion guide. [1][2][5]

Utilities

Scottsdale's sources don't agree on water and sewer:

• The zoning code says the owner "shall provide separately metered utilities (electrical, gas, water, and sanitary sewer)" to the ADU, "unless otherwise determined by the utility provider."
• The city's ADU page says electric and gas must be separately metered, but that water and sewer "will utilize the existing tap at the public water or sewer line," then branch on private property to separate connections to the ADU.

Ask the One Stop Shop which applies before you design your utility runs. The owner must also repair any public street or public property damaged while building the ADU. [1][2]

Fees and timeline

Scottsdale's FY 2026/27 application fee schedule (effective July 1, 2026) lists a $131 pre-application fee and a $131 "Development Review – Staff Approval" fee for ADUs. Building permit and plan review fees are separate and depend on the project. The city doesn't give permit fees over the phone; request an estimate through its fee estimate page. For budgeting, see our ADU cost guide.

Scottsdale's ADU sources don't give a set review time for the administrative application or the building permit. See our ADU permit process guide. [1][10][11]

Renting your ADU

Scottsdale says an ADU can be rented separately from the main home, and its code says no family, marriage or employment relationship with the owner is required. Total occupancy of the main home and all ADUs on the lot can't exceed six adults. An ADU can't be sold separately, and the lot can't be split or condo-platted to separate it.

Who must live on site. Scottsdale's sources differ:

• Zoning Ordinance Section 7.203 says an ADU that got its certificate of occupancy on or after September 14, 2024 "shall not be used as a vacation rental or short-term rental unless the property owner resides on the same property." The city's ADU FAQ says the same for short-term rentals.
• The city's ADU web page says the owner "must reside on the premise for any ADU that is rented, leased, offered for rent or lease, or occupied as a Vacation Rental or Short-term Rental," which reads more broadly.

Arizona law (ARS 9-500.39) lets a city require the owner of a short-term rental to live on the property if an ADU there got its final approval on or after September 14, 2024. ARS 9-461.18 bars a city from prohibiting the main home or an ADU from being "separately leased long-term rental housing" (90 days or more, or month to month). If you plan a long-term rental and won't live on site, confirm with the city.

Short-term rental license. Any rental of less than 30 days needs a Scottsdale vacation and short-term rental license for each property ($250 a year), an Arizona transaction privilege tax (TPT) license, at least $500,000 in liability coverage, and written notice to neighbors within 30 days of getting the license. [1][2][3][5][12][13][14]

Pre-approved plans

Arizona's pre-approved plan law, ARS 9-461.20 (SB 1529, 2025), says a city "shall establish standard preapproved housing design plans or a preapproved housing design plan program." Beginning July 1, 2026, in single-family areas that allow ADUs, it "shall create at least three standard preapproved housing design plans for accessory dwelling units," at 200, 600 or 1,000 square feet. A plan program must accept plan submissions from anyone and post approved plans on the city's website.

We didn't find a pre-approved ADU plan library on Scottsdale's website as of November 2026; its ADU page describes the pre-application, administrative review and permit review steps and doesn't mention pre-approved plans. Ask the One Stop Shop at 480-312-2500 whether pre-approved plans are available. [1][4][15]

Permit steps in Scottsdale

1. Check your lot

   The lot must be a single-family residential lot with a finished main home that has its certificate of occupancy. ADUs aren't allowed near military airports or in some areas near other airports where noise exceeds 65 decibels; the city says parts of Scottsdale are near Phoenix Sky Harbor and Scottsdale Airport, so ask the One Stop Shop whether your lot is affected. In northern Scottsdale, the ADU can't go in required Natural Area Open Space (NAOS). Check any HOA rules too. [2][3][6][7]

2. Submit a pre-application

   Start with an online Pre-Application request. The city encourages you to include a site plan, building elevations and utility information. The pre-application fee is $131. [1][10]

3. Pre-application meeting

   City staff schedule a meeting with you to go over the requirements for your proposed ADU. [1]

4. Formal application for administrative review

   After the pre-application, staff tell you how to file a development application for administrative review ($131 for an ADU staff approval). It must show a site plan, the main home's floor area, ADU plans that meet the size and setback rules, and utility connections. The Zoning Administrator can approve, approve with stipulations, or deny it, and the code says that decision is not appealable. [1][2][10]

5. Building permit review

   Once the administrative application is approved, you or your designer submit construction documents for permit review. A permit is issued after all code requirements are met. For a fee estimate, use the city's fee estimate request; estimates take 2 to 3 business days. [1][11]

6. Build, address and inspect

   Each ADU needs its own address, posted near its entrance and visible from the main street frontage, plus a separate exterior entrance and a path to the street that doesn't pass through the main home. [2]

Who to call

• Planning and Development One Stop Shop

  ADU pre-applications, permits and fee questions: OneStopShopStaff@ScottsdaleAZ.gov

  480-312-2500

  7447 E. Indian School Road, Scottsdale, AZ 85251 (Mon, Tue, Thu, Fri 8 a.m. to 5 p.m.; Wed 9 a.m. to 5 p.m.)

  [4]

• City of Scottsdale (main line)

  General city information

  480-312-3111

  3939 N. Drinkwater Blvd, Scottsdale, AZ 85251

  [1]

• Short-term rental licensing

  Vacation and short-term rental licenses (rentals under 30 days)

  [14]

Questions people ask