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Accessory Dwelling Units (ADUs)​

​What is an Accessory Dwelling Unit (ADU)? 

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​ADUs, often referred to as guest houses, casitas, or granny flats are separate, self-continued living areas that are either fully detached structures or attached to an existing home, with its own external kitchen. 

An ADU usually contains all of the amenities to operate as a fully independent, operational dwelling, including a kitchen, bathroom, living area and sleeping quarters. 

Example ADU floor plan:


New Rules​

​In late 2024, the Phoenix City Council approved new ordinance changes to comply with new state laws for ADUs


Learn More​​​


Curious if your property is suitable for an ADU?​


Check out the Frequently Asked Questions at the bottom of this page for basic, preliminary information.

Please consult with the Planning and Development Department before making any decisions to alter your property. ​​​​​


​​Contact Us

Have questions about ADUs? Send us an email!


PDD Ombudsman ​
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Frequently Asked Questions ​


What if I live in an HOA community? 

Check your HOA rules about accessory structures. 


I don't know if my home is in the correct zoning district. 

When a lot has no more than one single-family detached primary dwelling, two ADUs are permitted in addition to the primary dwelling unit. A third ADU may be pemittd under certain circumstances. Typical single-family zones are: R1-6, R-1-10...etc.

Use My Community Map​ to find out the zoning district for your home. 


How do I know if my lot is large enough to fit an ADU?

​Each zoning district has “lot coverage" guidelines that define how much of your property can be covered by buildings or structures. The new guest house rules allow two ADUs per lot (and even three on certain lots), and each ADU may be up to 75% of the gross floor area of the main house (not to exceed 1,000 sf for lot up to 10,000 sf or 3,000 sf for lots over 10,000 sf).

In My Community Map​, link to the Phoenix Zoning Ordinance to determine the lot coverage allowance for your home. 

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Where can I find my lot size?

​​Find your property on the Maricopa County Assessor's Office website. It will list your official lot size as well as the dimensions of the structures on your property. You can use these two figures to make a rough calculation of your current lot coverage.