Arizona ADU law in cities over 75,000 (A.R.S. 9-461.18): what it allows on a lot
ADU law in cities over 75,000 (A.R.S. 9-461.18) is Arizona law, and the official source is at azleg.gov.
A city of more than 75,000 people must allow at least one attached and one detached accessory dwelling, up to 75 percent of the house's floor area or 1,000 square feet, wherever a single family home is allowed, with no extra parking, side and rear setbacks of no more than 5 feet, and no rule on who lives in it. A city that missed the January 1, 2025 deadline must allow them on every residential lot without limits.
Whether it applies to one lot turns on where the lot is and what it is zoned; the city, county or state office named in the law decides. Mapped areas are approximate. This is a plain reading of public law with its source, not legal advice.
Free, no account. ParcelSheet shows the lot's mapped size, parcel lines and flood zone, and this law on the lot's Arizona sheet.
Other Arizona laws on a lot: Middle housing (HB 2721, 2024).