How much does it cost to build a casita in Arizona?

Our cost model uses an average of about $250 per square foot for a high-quality ADU, so a 600-square-foot casita runs roughly $150,000 before site-specific work such as utility runs, grading or HOA-required details.

Do I need a permit to build a casita?

Yes. A casita or ADU needs building permits, and the plans must meet your city’s zoning and building codes. We handle the permitting, engineering and inspections.

Can I rent out my casita?

Arizona’s ADU law prevents covered cities from requiring owner-occupancy, but short-term rental rules and your HOA’s covenants may still limit rentals. We check both during design.

Will my HOA allow a casita?

Arizona’s ADU law limits what cities can require, but private HOA covenants still apply. We review your CC&Rs and prepare the architectural submission.

Casita & ADU Builders in Phoenix | Guest Houses

A casita is more than another room

One of the biggest misconceptions is that a casita is simply adding a room. In reality a guest house involves electrical planning, plumbing, HVAC, exterior matching, roofing coordination, a separate entrance, privacy planning and a layout that works on its own. That is why planning and organization matter so much — and why we handle design, HOA requirements, permitting, CAD visuals, construction and project management as one team.

What Arizona’s ADU law changed

Arizona’s 2024 accessory dwelling unit law (HB 2720) requires cities and towns with more than 75,000 residents to allow, as a permitted use, at least one attached and one detached ADU on a single-family lot. Covered cities had to adopt their rules by January 1, 2025. Among other things, they may not require owner-occupancy or extra parking, may not require the ADU to match the main house, and may not require side or rear setbacks of more than five feet. An ADU can be up to 1,000 square feet or 75% of the main home, whichever is smaller.

That covers Phoenix, Scottsdale, Mesa, Chandler, Gilbert and Tempe. Smaller towns such as Paradise Valley and Fountain Hills fall below the threshold and keep their own rules — see remodeling in Paradise Valley. Private HOA covenants still apply everywhere, so we review your CC&Rs during design. Our permits & HOA guide explains the process city by city.

Casita or addition?

An attached addition shares the main home’s systems and is convenient in summer heat; a detached casita gives guests and family real privacy. Our home additions page and home addition cost guide cover the attached route, and garage remodeling covers converting space you already have. See Jeff’s guest house for a finished project.