Maricopa County, AZ Accessory Structures: ADU Rental Restrictions (2026)

3 of the Zoning Ordinance treats ADUs as a permitted use on any lot zoned for single-family residential, stating that "in accordance with Arizona State Statute, ADUs are a permitted use on any lot or parcel zoned for single-family residential use. " Every qualifying lot must allow at least one attached and one detached ADU, and a lot of one acre or more must allow an additional detached ADU provided one of the ADUs on the lot is deed-restricted as affordable housing for households earning up to 80% of area median income.

On the rental side, the Occupancy and Tenancy provision is direct: "ADUs may be leased or occupied independently of the principal dwelling as long-term rental housing," and "no familial, marital, or employment relationship is required between occupants of the principal dwelling and the ADU" - so an owner can lease the ADU to an unrelated tenant as an ordinary rental. 4, which also require the property owner to live on site whenever the ADU is being used as an STR unless a certificate of occupancy for the ADU predates September 13, 2024.

Size is capped at 75% of the primary dwelling or 1,000 square feet, whichever is less, on lots under an acre, and no ADU may exceed the size of the principal dwelling on any lot. Detached ADUs built into a required side or rear yard cannot occupy more than 30% of that yard, must sit at least five feet from the side or rear lot line, and are limited to 18 feet in height if they encroach into the required yard. An ADU lawfully built before this Article was adopted keeps legal nonconforming status, but any alteration or expansion must bring it into compliance with the current Article.