From Permits to Final Walkthrough
ADU & Casita Permits in Phoenix, Step by Step
A casita needs a building permit, and the path runs through zoning, plans, plan review and inspections. We pull the permits ourselves. Here's what Arizona law and the City of Phoenix allow, and how the permit works.
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Can I build an ADU on my property?
In most of the Phoenix area, yes. Arizona law requires every city or town with more than 75,000 people to allow at least one attached and one detached ADU on any lot zoned for a single-family home. That covers Phoenix (including Laveen), Avondale, Goodyear, Buckeye, Glendale and Peoria.
Your lot still decides where the casita goes and how big it can be: zoning, setbacks and any HOA rules. We check all three before design starts, so the plan fits what your lot allows.
Sources: A.R.S. 9-461.18 (azleg.gov)
What does Arizona's ADU law say?
Arizona's 2024 ADU law, HB 2720, added section 9-461.18 to the state statutes. It applies to cities and towns with more than 75,000 people. In those cities:
- At least one attached and one detached ADU must be allowed on any lot where a single-family home is allowed.
- One more detached ADU must be allowed on lots of one acre or more, when at least one ADU on the lot is restricted affordable housing.
- The city must allow an ADU of up to 75% of the main home's floor area or 1,000 sq ft, whichever is less. Floor area means interior living space.
- An ADU is a permitted use: no public hearing, variance or special permit is needed.
- Side and rear setbacks for an ADU can't be more than 5 feet.
- The city can't require added parking for an ADU, or a fee in place of parking.
- The city can't require the ADU to match the home's exterior design, roof pitch or finish materials.
- The city can't ban renting the home or the ADU separately as a long-term rental (90 days or more, or month to month), and can't require the person living in the ADU to be family.
Sources: A.R.S. 9-461.18 (azleg.gov)
What doesn't the ADU law change?
Building, fire and safety codes still apply, and every ADU still needs a building permit, though a city can't require fire sprinklers or the commercial building code. Private HOA rules (CC&Rs) can still limit ADUs, because the law only restricts what cities can require. Land near a military airport is exempt, which can matter in parts of the West Valley near Luke Air Force Base. Cities and towns under 75,000 people, and unincorporated county land, set their own rules.
Sources: A.R.S. 9-461.18 (azleg.gov)
How do you check if your lot can fit an ADU?
Three lookups. Find your zoning district on the City of Phoenix's My Community Map; typical single-family zones are R1-6, R1-10 and similar. Find your lot size and the size of your buildings on the Maricopa County Assessor's website, which gives you a rough idea of how much of the lot is already covered. Then check your HOA's rules on accessory structures.
Or send us your address and we'll go through it with you.
Sources: City of Phoenix ADU page
How many ADUs can you build in Phoenix?
Two on a single-family detached lot. A third is allowed on lots of one acre or more when one of the units is deed-restricted affordable housing. A lot that already has a duplex or triplex can't add an ADU.
Sources: City of Phoenix ADU page; Phoenix Beginner's Guide to ADUs
How big can an ADU be in Phoenix?
On lots up to 10,000 sq ft, an ADU can be up to 1,000 sq ft or 75% of the main home's floor area, whichever is less. On larger lots, the limit is the smallest of 3,000 sq ft, 10% of the net lot area, or 75% of the main home.
All five of our casita designs are under 1,000 sq ft, so on most lots the 75% rule is the one to check. Here's the smallest main home each design fits:
| Design | Size | Main home needs at least |
|---|---|---|
| The 345 | 345 sq ft | 460 sq ft |
| The 492 | 492 sq ft | 656 sq ft |
| The 720 | 720 sq ft | 960 sq ft |
| The 864 | 864 sq ft | 1,152 sq ft |
| The 990 | 990 sq ft | 1,320 sq ft |
Sources: Phoenix Beginner's Guide to ADUs
How close to the property line can a casita be in Phoenix?
A detached ADU can sit in the rear yard, 3 feet from an interior lot line, 5 feet from a street-side lot line and 0 feet from a dedicated alley. It can't be taller than 15 feet without a use permit. An attached ADU stays at least 3 feet from the rear lot line and 5 feet from a side lot line.
Sources: Phoenix Beginner's Guide to ADUs
Step 1 of 4
What plans does the city need to see?
A full set of drawings: a site plan showing where the casita sits, floor plans, elevations and structural engineering. We prepare the set for the design you choose.
Step 2 of 4
How long does plan review take?
On most casitas we plan 3-4 months for plans and permits before construction starts. We submit the plans and answer the city's comments along the way.
Step 3 of 4
What inspections does a casita need?
The city inspects at set stages, such as foundation, framing, and the electrical, plumbing and mechanical rough-ins, then a final inspection. We schedule each one as the build moves forward.
Step 4 of 4
What happens after the final inspection?
Once the final inspection passes, we walk the finished casita with you.
ADU permit questions
Who pulls the permit, me or the contractor?
We do. R&M prepares the plans and pulls the permits for the casitas we build.
How long do casita permits take?
On most casitas we plan 3-4 months for plans and permits before construction starts. Your schedule is set during planning.
Does my HOA need to approve a casita?
If your home is in an HOA, usually yes. Arizona's ADU law limits what cities can require, but it leaves private HOA rules (CC&Rs) in place, so an HOA can still restrict ADUs. We check the HOA's rules along with the city's.
Can I rent out my casita in Phoenix?
Long term, yes. In Arizona cities over 75,000 people, the city can't ban renting an ADU for 90 days or more, or month to month. Phoenix's ADU guide also allows short-term rentals; check the city's short-term rental rules first.
Do I need extra parking for an ADU?
Not for a new ADU in Arizona cities over 75,000 people. Converting a garage or carport in Phoenix is different: you need equivalent parking elsewhere on the lot, not in the front setback.
"Fantastic work by Ramiro and team. They provided a competitive quote. They helped with the process of permitting and HOA approvals. They provided a clear quote. He stayed in constant contact to keep us informed of progress. He made sure that quality work was done in every aspect. We converted a part of our home into an ADU and have since moved in. We are extremely happy with the finished product!"
"We hired R&M to build a casita for us and the experience was excellent from start to finish. Ramiro and his team handled everything- design, permits, construction, which made the whole process smooth and stress-free. They turned our vision into a reality. We were on a schedule and the project was completed in about 7 months, and the quality of work and communication throughout was outstanding. If you're looking to build a casita, I highly recommend!"
Not sure what your lot allows?
Send us your address and we'll look at zoning, setbacks and HOA rules with you.
Proudly Serving Metro Phoenix & Maricopa County
Based in Laveen, we build across Phoenix and the West Valley: Avondale, Goodyear, Buckeye, Glendale and Peoria. We also take projects in Scottsdale, Mesa, Tempe, Chandler, Gilbert and across Maricopa County.
Call or request a project consultation. We build ADUs, custom homes, and additions across the Valley.
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R&M Construction & Development
Licensed Residential & Commercial Builder
AZ ROC #363967 · 10 years in business · Locally owned