Homeowner Guide
Casita vs ADU: What's the Difference?
Most of the time, these two words describe the same thing: a separate living space on the same property as your main home. ADU stands for accessory dwelling unit and is the term you will see on city paperwork. Casita is the word most Arizona homeowners actually say out loud.
The word you use does not change what gets reviewed. Your city or county looks at the structure itself: how it is built, where it sits and how it will be used. That is the part worth focusing on.
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Serving Homeowners Statewide
Casita & ADU Specialists
How Homeowners Use the Space
- Parents
- A private, close-by space for aging parents who want independence without living far away.
- Adult Children
- Room for a grown child who is saving money, in school or starting out.
- Guests
- Visitors get their own space, and so does everyone in the main house.
- Home Office
- A quiet, separate place to work that is not the kitchen table or a spare bedroom.
- Long-Term Living Space
- Some homeowners plan to live in the casita themselves later on.
- Rental Use Where Legally Permitted
- Where local rules and any HOA documents allow it, some homeowners rent the space.
- Extra Private Space
- A studio, a hobby room or simply more room to breathe on a property you already own.
Common Questions
- What is the difference between a casita and an ADU?
- In everyday Arizona use, they usually describe the same thing: a separate, smaller living space on the same property as a main home. ADU, short for accessory dwelling unit, is the term cities and building departments tend to use. Casita is the everyday word many Arizona homeowners use.
- Does a casita have to have a kitchen?
- It depends on the plan you choose and on local requirements for the property. Some spaces are designed as full independent living units, others as guest or office space. What is permitted is confirmed during property review and permitting.
- Is a casita the same as a guest house?
- Guest house is another informal term homeowners use for a similar structure. What matters for your project is how your city or county classifies the space, not which word you use.
- Can I rent out the space?
- Rental use depends on local rules and any restrictions that apply to your property, including HOA documents. Verify what is permitted for your address before planning around rental use.