Casita Floor Plans

Before you pick a casita floor plan, find out how big your casita is allowed to be. In Maricopa County, that depends on the size of your main home.

How big can your casita be?

Under HB 2928, a county must allow an ADU of at least 75% of your main home’s floor area or 1,000 square feet, whichever is less. A county may allow larger. Here is how that works out:

• A 1,200 sq ft home: the county must allow at least 900 sq ft.
• A 1,600 sq ft home: 75% is 1,200, so the 1,000 sq ft limit applies.

Cities have their own rules, so confirm your jurisdiction first. We cover that in 4 things to check before you build a casita in Maricopa County.

Typical casita layouts

These ranges are typical, not limits. Your lot and budget decide the final plan.

• Studio, about 300–500 sq ft: one open room for living and sleeping, a kitchenette, and a full bath. This is the most compact option.
• One-bedroom, about 500–750 sq ft: a separate bedroom, a real kitchen, and a living area.
• Two-bedroom, about 750–1,000 sq ft: room for a family member, a long-term tenant, or a home office. A 750 sq ft casita needs a main home of at least 1,000 sq ft to be covered by the county minimum.

What to plan for in Arizona

• Outdoor living. A covered patio or glass doors that open to the yard add usable space without adding square footage.
• Sun and shade. Window placement and roof overhangs matter in the desert.
• Storage. Casitas run out of closet space first.
• Your yard. Setbacks, utility easements, and HOA rules can shape the footprint before the floor plan does.

A floor plan only works if it fits your property. Our free site evaluation checks your lot and your HOA documents before you spend anything on design. Browse our casita designs, see what a casita costs to build, or contact us.

Frequently asked questions

How big can I build my casita in Maricopa County?

A county must allow an ADU of at least 75% of your main home’s floor area or 1,000 square feet, whichever is less. A county may allow larger, so confirm the limit for your parcel.

Can I build a casita larger than 1,000 square feet?

Possibly. The 1,000 sq ft figure is what a county must allow at minimum, not a ceiling. Ask the county whether it allows larger on your lot.

Is there a minimum casita size in Arizona?

HB 2928 sets no minimum size for an ADU. Building code and county requirements still apply to any livable unit, so confirm with the county.