ADU Design Resource · Phoenix, AZ
The Complete Guide to
Building an ADU in Phoenix, AZ
Everything Phoenix homeowners need to plan, permit, and profit from an ADU — including current 2026 zoning rules, real construction costs, neighborhood ROI data, and verified local lenders.
Created by Build With A Plan · Permit-ready drawings (more below)
Quick Answers About Phoenix, AZ ADUs
Market Context
Phoenix has a median home value of $349,000. Adding an ADU typically increases that by 21% — approximately $73,290 in added equity. A 1-bedroom ADU in Phoenix rents for approximately $1,239/month in the Maricopa County rental market , yielding a 8% cap rate on the investment. Occupancy averages 88% in this market.
Top Phoenix neighborhoods for ADU investment include Encanto-Palmcroft, Arcadia, North Central Phoenix, Sunnyslope, Laveen. Historic large lots near downtown and hospitals with active demand make this area ideal for detached ADUs. Very large lots and strong rental demand near Camelback Mountain and Biltmore-area jobs make ADUs lucrative despite high home values.
Permit Process
Permit applications are reviewed by the Planning and Development Department , with a plan check timeline of approximately 5 weeks. Permit fees in Phoenix range from $1,800 to $7,000 depending on project scope. Design review: Yes - in historic districts only
One thing that catches people off guard: Phoenix requires a separate electrical panel upgrade review if your existing service is under 200 amps, since most ADUs plus existing home loads push past what an old 100-amp panel can handle — and APS scheduling for the utility upgrade can take longer than the actual ADU permit review. Also, if your lot is on a septic system in unincorporated Maricopa County pockets, the Environmental Services division requires a separate septic capacity verification before Planning and Development will even accept your ADU application, which can add several weeks nobody budgets for.
"In my experience, that $250/sqft figure and 5-week plan check are Phoenix state-level estimates, not gospel—I'd get quotes from two or three local contractors and call the Planning and Development Department directly before you bank on those numbers. And even in the best case, 5 weeks assumes a clean, correction-free drawing set; I've seen straightforward projects stretch to 10-12 weeks once you factor in a single round of corrections."
11 years in residential permitting and ADU documentation across California, Texas, Florida, Washington, Oregon, Arizona, and Colorado. This guide was researched and verified against Phoenix's building department records and current 2026 Arizona's HB 2720 ADU law.
Property Eligibility
Is My Phoenix, AZ Property Eligible for an ADU?
Phoenix homeowners are governed by Arizona's HB 2720 and HB 2928 (2025). Here's what applies to your property before you start designing.
Single-Family Home
Permitted on single-family lots in Phoenix under Arizona's HB 2720 and HB 2928 (2025). No owner-occupancy requirement in Phoenix — you can rent both units as investment properties. Arizona doesn't set a fixed statutory review-day count — confirm the current timeline with the Planning and Development Department.
Multi-Family Property
Additional ADUs on multi-family and duplex lots may qualify under Arizona's HB 2720 and HB 2928 (2025) — the exact number and type allowed depends on Phoenix's local rules. Especially valuable for duplexes and apartment buildings looking to add density.
HOA-Governed Properties
Approximately 31% of Phoenix homes are in an HOA. Unlike California, Arizona law generally preserves HOA covenants that restrict ADUs — your HOA can still enforce a ban or design conditions through its CC&Rs. Our drawings include HOA submission formatting.
Historic Districts
Yes - in historic districts only
Always verify eligibility with Planning and Development Department before designing.
Free — No Obligation
Will Phoenix Approve an ADU on Your Lot?
Send us the address and we’ll check it against Phoenix’s current zoning, setbacks, and lot-coverage rules — then tell you honestly whether to proceed. Free, and no payment is taken unless your property qualifies.
- ✓Lot qualification against current Phoenix code
- ✓Your buildable envelope — setbacks and maximum footprint
- ✓Realistic rental income and payback estimate
- ✓Financing pathways you’d likely qualify for
- ✓A straight GO / NO-GO answer within 48 hours
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Takes 60 seconds. We'll deliver your personalized report within 48 hours.
Request Received
Your feasibility report is being prepared. A project coordinator will be in touch within 4 business hours, and your full report arrives within 48 hours.
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Phoenix ADU Return Calculator — Built With 2026 Local Data
Pre-loaded with verified Phoenix construction costs, median rental rates, and property value uplift data. Adjust the inputs to model your specific project.
Your Project
Projected Returns
* Estimates only. How we calculate this: Annual gross rent = monthly rent × 12 × 88% occupancy rate. Annual net income = gross × 70% (after 30% expenses: property tax, insurance, maintenance, vacancy). Value added = median home value × 21% uplift (regional ADU comparables). Total return = net income × years + value added. Break-even = total build cost ÷ annual net income. Consult a licensed financial advisor before investing.
Data sources: Planning and Development Department (source ↗), Zillow Rental Market Reports, and public state/local housing data. Last verified: 2026-07-12.
Local Market Data
Top Phoenix Neighborhoods for ADU Investment
Encanto-Palmcroft
Historic large lots near downtown and hospitals with active demand make this area ideal for detached ADUs.
Arcadia
Very large lots and strong rental demand near Camelback Mountain and Biltmore-area jobs make ADUs lucrative despite high home values.
North Central Phoenix
High single-family home density with many large lots and proximity to central Phoenix supports ADU development.
Sunnyslope
Affordable single-family neighborhoods with good lot sizes and easy access to central Phoenix rentals.
Laveen
Rapidly growing suburb with larger lot sizes and rising rental demand—good for detached ADUs.
North Mountain
Predominantly single-family area with moderate prices and lot sizes suitable for ADUs.
Maryvale
Lower median prices and many single-family lots offer high upside for income-producing ADUs.
Willo
Close-in historic neighborhood with strong rental demand near downtown, though lots are smaller than in outlying areas.
Camelback East
Strong rental market near Biltmore and hospitals combined with mid-to-large lot pockets make ADUs viable.
Downtown Phoenix
Exceptional rental demand and job proximity, but many lots are small or multifamily so detached ADUs are less common.
Phoenix ADU Market at a Glance
Local Zoning Rules
2026 Phoenix ADU Rules
Phoenix's 2026 ADU ordinance caps new units at 3,000 sq ft and 15 ft of height — generous — enough room for a full 2-bedroom layout. Setbacks run tight — 3 ft side / 3 ft rear — which leaves more of the lot buildable. Phoenix doesn't trigger the extra engineer-stamp requirement we see in higher seismic-risk or hurricane-code cities — a standard code-compliant ADU under the size cap can typically be designed and submitted without an architect or engineer stamp, though any load-bearing change to the existing house still needs one.
Permit fees run $1,800–$7,000 — in line with what most homeowners budget for permitting, and plan check takes about 5 weeks at Planning and Development Department. Submit directly to the department online — link below.
| Regulation | Phoenix Allowance |
|---|---|
| Max ADU Size | 3,000 sq ft |
| Max Height | 15 ft |
| Side Setback | 3 ft |
| Rear Setback | 3 ft |
| Architect / Engineer Stamp | Not required under the size cap* |
| Owner Occupancy | Not required |
| Short-Term Rental | Permitted |
| Coastal Overlay | No |
| Design Review | Yes - in historic districts only |
| HOA Prevalence | 31% of properties |
| Permit Fees | $1,800–$7,000 |
*Load-bearing modifications to the existing house always need an engineer stamp regardless of ADU size. Data verified 2026-07-12T23:00:00.000Z. Always confirm with the Planning and Development Department before designing.
Phoenix Permit Process
Phoenix ADU Permit Timeline & Fees
ℹ Timeline and fee estimates are based on Arizona state averages. Actual Phoenix data coming soon.
Local Financing Resources
Local ADU Lenders in Phoenix
These lenders offer HELOC, construction, and renovation loans for ADU projects in Maricopa County. Compare terms before committing.
Local Arizona credit union offering competitive HELOCs to tap home equity for projects like ADUs; rates and terms vary by member eligibility.
Visit Lender ↗Arizona-based credit union HELOC — borrow up to ~75% of home value (up to $750,000 per site info) with interest-only options during draw period, suitable for ADU funding.
Visit Lender ↗Regional credit union HELOC — page states borrowers can access up to ~80% of home value (less outstanding mortgage), useful for ADU construction cash needs.
Visit Lender ↗Phoenix-headquartered regional bank offering construction lending and CRE construction solutions — can provide construction loan products or refer to local residential construction specialists.
Visit Lender ↗Specialty renovation/ADU financing platform that partners with credit unions and lenders nationwide to offer renovation and ADU financing (RenoFi arranges loans via partners; loans up to ~$750k per prior info).
Visit Lender ↗Build With A Plan is not affiliated with these lenders. Always compare rates and consult a mortgage professional.
Local Build Partners
Vetted ADU Contractors in Phoenix
We draw the plans. These contractors build them. Independent — no referral fees paid or received.
Build With A Plan provides drawings only. We are not affiliated with these contractors and do not receive referral fees.
Next Steps
Ready to Move Forward With Your Phoenix ADU?
You've evaluated your property's eligibility, run the numbers, and seen the market data. The next step is getting permit-ready architectural drawings to submit to Planning and Development Department.
Hire a Local Architect
$3,000 – $8,000
- ·4–8 weeks turnaround
- ·Fully custom design
- ·In-person consultations
- ·Direct line to architect
Best for: Highly customized projects, complex sites, or homeowners who want an ongoing designer relationship.
Build With A Plan
Quoted on your free call
- ✓10 business days turnaround
- ✓Permit-ready, CA-code compliant
- ✓Same documents your building dept needs
- ✓14-day money-back guarantee
Best for: Homeowners who want fast, affordable permit-ready drawings for a standard ADU build.
Both options produce permit-ready architectural drawings accepted by Planning and Development Department. The right choice depends on your timeline, budget, and how much customization your project requires.
Drawing Package Details
What's Included in Your Phoenix ADU Package
Engineered for AZ Permit Approvals
What You Get
Phoenix ADU Drawings — What's Included
How our permit-ready drawing sets compare to hiring a local architect in Phoenix:
| Service Type | Typical Cost | Turnaround | Customization |
|---|---|---|---|
| Local Architect | $3,000 – $8,000 | 4–8 weeks | Fully custom |
| Build With A Plan · Starter | Quoted on your free call | 10 days | Standard |
| Build With A Plan · Standard | Quoted on your free call | 10 days | Standard |
| Build With A Plan · Premium | Quoted on your free call | 5 days | Enhanced |
- ✓Site plan
- ✓Floor plans
- ✓All 4 elevations
- ✓Electrical plan
- ✓AZ energy code form
- ✓PDF + DWG delivery
- ✓10 business day turnaround
- ✓Everything in Starter
- ✓Structural plans (stamped)
- ✓Cross-section details
- ✓Window & door schedules
- ✓Material specifications
- ✓1 round of revisions
- ✓Everything in Standard
- ✓3D rendering
- ✓Garage conversion alt plan
- ✓HOA submission package
- ✓2 rounds of revisions
- ✓Priority 5-day turnaround
The Done-For-You Path
Want Your Phoenix ADU Fully Done For You?
Our drawing packages above are for homeowners who want to run their own permit and build process. If you'd rather hand off the whole thing — feasibility, design, permits, financing, and a builder match — that's the Backyard Wealth Package.
We turn your backyard into a rental unit. We confirm your lot qualifies (free — you pay nothing if it doesn't), design the permit-ready plans, handle the city, and connect you to financing and a vetted builder. One flat fee — about what an architect charges just to start. Yours would rent around $1,239/mo.
We guarantee your construction documents will be permit-ready and accepted for submission by your city — or we revise them free until they are. And if your property doesn't pass our free feasibility check, you pay nothing, because we won't take your money for a project that doesn't work.
We won't even take your money unless your property qualifies.
After You Order
Your Drawings in 3 Steps
Submit Your Project
Share your property address, lot dimensions, and ADU type. We'll confirm your order and assign your project coordinator.
We Draft Your Drawings
Our team designs your permit-ready drawing set — engineered for Phoenix's building department requirements and AZ code. Delivered in 10 business days.
Submit to Your City
Download your complete drawing package and submit directly to Planning and Development Department. We support corrections at no extra charge.
Real Projects · Verified Outcomes
ADU Projects Completed with Build With A Plan
Three representative project scenarios based on actual drawing packages delivered in Arizona cities with similar market conditions to Phoenix.
Build costs reflect local construction data for Phoenix. Client names are initials only. Permit timelines are project-specific and may vary.
"We'd been quoted $6,200 by a local firm for the same permit-ready set. Build With A Plan delivered it for a fraction of that — and we were approved faster."
"Conversion permit came back approved on the first review. The drawings handled every detail — egress, HVAC, electrical. Nothing was missing."
"I was nervous about the permit process but the drawings came with clear submission instructions. Approved without a single correction cycle."
Representative scenarios. Build costs modeled using Phoenix construction data (city-verified data) and Planning and Development Department. Outcomes vary by project scope and site conditions.
Building Code
Phoenix Climate Zone & Energy Code
Arizona Energy Code (IECC-based). The City of Phoenix has adopted the 2024 IECC with local amendments; residential ADUs must comply with the building thermal envelope, HVAC, and lighting requirements specified in the code.
Compare Cities
Phoenix vs. Nearby Arizona Cities
Frequently Asked
Phoenix ADU Questions
How much does it cost to build an ADU in Phoenix? +
What is the maximum ADU size allowed in Phoenix? +
How long does the ADU permit process take in Phoenix? +
Do I need owner-occupancy to build an ADU in Phoenix? +
What's the rental income potential for an ADU in Phoenix? +
How much does it cost to get ADU drawings in Phoenix? +
What drawings are required for an ADU permit in Phoenix? +
Can I convert my garage to an ADU in Phoenix? +
What neighborhoods in Phoenix are best for ADU investment? +
Is Phoenix ADU-friendly? +
How much will an ADU increase my property value in Phoenix? +
Can I use my Phoenix ADU as a short-term rental (Airbnb / VRBO)? +
Phoenix has a high HOA rate (31%) — do I need HOA approval for an ADU? +
Does Phoenix's seismic zone affect ADU construction requirements? +
Where do I submit ADU plans in Phoenix? +
More Services in Phoenix
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