An ADU builder in Mesa is a licensed contractor who designs and constructs accessory dwelling units — detached backyard units, garage conversions, attached additions, and junior ADUs (JADUs). Because an ADU is a complete second dwelling, the builder coordinates foundation, framing, plumbing, electrical, and HVAC work and pulls it through Mesa's permit process and utility connections. Not every general contractor has built one, so the right builder is one with ADU-specific experience in Arizona.
What ADU Builders Cost in Mesa [16][17][18]
Based on our Mesa cost data, expect the following ranges from local ADU builders. Quotes for the same scope typically vary 20-40% between contractors, so getting at least three bids is the single best way to control cost.
| New Detached ADU (all-in) | $150,000-$280,000 |
| Cost per Sq Ft | $175-$350 |
| Garage Conversion | $80,000-$150,000 |
| Prefab / Modular ADU (installed) | $150,000-$300,000 |
| City Permit & Plan Review | Valuation-based (Development Services Schedule of Fees, July 2026): $500 plus $6 per $1,000 of valuation over $25,000, up to $200,000; then $1,550 plus $9 per $1,000. A $150,000 ADU pays about $1,250 and a $250,000 unit about $2,000, plan review and trade permits included. |
| Impact Fees | City Code Title 5 Ch. 17 lists a Public Safety impact fee of $402 per detached single-residence dwelling unit ($388 attached) on the schedule as of June 30, 2025, and Code 5-13-2 a Solid Waste Residential Development Fee of $311 per dwelling unit (July 2026 schedule). Water impact fees were replaced on January 1, 2026 by Water and Wastewater Capacity Fees (Code 8-10-13), charged only where a new or larger service connection is needed; because 11-31-3(H)(2) requires an ADU to share the house's meters, a standard ADU should not trigger them. Neither schedule has an ADU line, so confirm with Permit Services (480-644-4273) whether the public-safety and solid-waste fees are assessed on your unit before budgeting. |
For a full line-item breakdown, see our Mesa ADU cost guide. To confirm what you're allowed to build before you hire, review the Mesa ADU rules (max detached size: 75% of the primary residence's interior habitable area or 1,000 sq ft, whichever is less (11-31-3(C)); a 1,200 sq ft house allows up to 900 sq ft, a house of 1,334 sq ft or more allows the full 1,000. Since Ord. 5950 (Aug 2025) the ADU no longer counts toward the cap on combined detached accessory floor area in 11-30-17(A)(4). District lot-coverage and building-coverage limits still apply (11-31-3(E)).; owner-occupancy: Not required. Neither 11-31-3 nor state law requires the owner to live on site, and ARS 9-461.18(B)(2) bars any family, marital or employment relationship test between the house and ADU occupants. The ADU may be leased separately long-term (ARS 9-461.18(B)(1)) but may not be sold separately from the primary residence (city ADU page).).
Get Free ADU Quotes in Mesa
Tell us about your project and we'll pass it to ADU builders serving Mesa. Free, no obligation — you choose who to work with. We don't have builders in every area yet; if nobody covers yours, we'll email you to say so.
Takes about a minute.
Up to 5 independent local ADU builders — never more, and we tell them nothing you don't submit here.
Compare quotes, verify license & insurance, hire (or don't). No spam either way.
🔒 Your info is secure. We share it only with contractors quoting your project. No spam, no obligation.
Just browsing? Search ADU builders near you by ZIP code.
How to Vet an ADU Builder in Mesa
- License: Confirm a current contractor's license in Arizona and that it's in good standing. Ask for the license number and verify it with the state board.
- ADU-specific experience: Ask how many ADUs they've completed in or near Mesa and request addresses or photos. ADU permitting and setbacks differ from a kitchen remodel.
- Portfolio & references: Get references from recent ADU clients and, if possible, visit a finished unit.
- Insurance: Verify general liability and workers' compensation coverage. Ask for a certificate of insurance.
- Written, detailed bid: Insist on an itemized, fixed-price or clearly-scoped bid — not a verbal estimate. It should state whether permits (Valuation-based (Development Services Schedule of Fees, July 2026): $500 plus $6 per $1,000 of valuation over $25,000, up to $200,000; then $1,550 plus $9 per $1,000. A $150,000 ADU pays about $1,250 and a $250,000 unit about $2,000, plan review and trade permits included.), plan check (Full residential plan review within the 10-working-day target; a non-refundable $500 application deposit (valuations $25,000-$200,000) is credited to the permit fee. Fourth and later re-submittals before issuance cost $120 per staff hour (2-hour minimum) and post-permit addenda $120 per hour with a $120 deposit. Plans are checked against the 2024 IRC and companion codes with Mesa amendments and the 2023 NEC; state law bars a fire-sprinkler or commercial-code requirement for an ADU (ARS 9-461.18(D)).), and impact fees (City Code Title 5 Ch. 17 lists a Public Safety impact fee of $402 per detached single-residence dwelling unit ($388 attached) on the schedule as of June 30, 2025, and Code 5-13-2 a Solid Waste Residential Development Fee of $311 per dwelling unit (July 2026 schedule). Water impact fees were replaced on January 1, 2026 by Water and Wastewater Capacity Fees (Code 8-10-13), charged only where a new or larger service connection is needed; because 11-31-3(H)(2) requires an ADU to share the house's meters, a standard ADU should not trigger them. Neither schedule has an ADU line, so confirm with Permit Services (480-644-4273) whether the public-safety and solid-waste fees are assessed on your unit before budgeting.) are included.
- Permit handling: Confirm they manage Mesa's permit process ("By-right building permit through Development Services' DIMES online portal (Accella); a code-compliant ADU needs no use permit, hearing or neighbor notice (ARS 9-461.18 'permitted use'). Submit a fully dimensioned site plan, code data sheet with scope of work, architectural and structural plans, and electrical, plumbing and mechanical plans (contractor licence verification form if a contractor pulls the permit); in a Historic District a Certificate of Appropriateness comes first. Inspections are booked online, by phone or text (Mon-Fri 6:30 am-5 pm); a permit is valid 180 days from issuance. Permit Services: PermitServices@mesaaz.gov, 480-644-4273, 55 N. Center St.", typically Written plan-review comments or approval within 10 working days (Monday-Thursday, excluding holidays) per Mesa's Residential Construction page; an expedited 5-working-day review costs an extra 100% of the permit fee. Allow for at least one re-submittal cycle.) and who is responsible if revisions are required.
- Payment schedule: Avoid large upfront payments. A reasonable schedule ties payments to completed milestones.
Questions to Ask Before You Hire
- How many ADUs have you built in Mesa in the last two years?
- Is your bid fixed-price, and what would trigger a change order?
- Are permits, plan check, and utility connection fees included?
- What's a realistic timeline, including permit review (Written plan-review comments or approval within 10 working days (Monday-Thursday, excluding holidays) per Mesa's Residential Construction page; an expedited 5-working-day review costs an extra 100% of the permit fee. Allow for at least one re-submittal cycle.) and construction?
- Who is my point of contact and how are delays communicated?
- What warranty do you provide on workmanship?
- Can you share three recent Arizona ADU client references?
Finance Your ADU Project
Most ADU projects are funded through HELOCs, construction loans, or cash-out refinancing. Compare rates from top lenders.
Some links on this page are affiliate links. We may earn a commission at no extra cost to you. Learn more
Are you an ADU builder? Get Mesa leads
Homeowners on this page submit real ADU project requests in Mesa. Each one goes to up to five local builders — that is what the homeowner agrees to — so claiming never takes it from anyone and there is no bidding. In practice far fewer ever make contact, which is why the number is five rather than three. A flat $50 only on the leads you accept: no subscription, no contract, and you deal with the homeowner directly.
Get Mesa ADU Leads →Frequently Asked Questions
How much do ADU builders charge in Mesa?
How do I find a good ADU builder in Mesa?
Do ADU builders in Mesa handle permits?
How long does it take to build an ADU in Mesa?
Get Free ADU Builder Quotes in Mesa
Compare bids from experienced local Mesa ADU builders. Free, no obligation.
Get Free Quotes →