Build to suit
Can I put two homes on one lot?
Maricopa County's ADU rules, including the December 2025 update.
Short answer
Generally one main home per lot, plus an accessory dwelling unit (ADU) or guest house within set limits, not two full, independent homes.
Rio Verde and Far North Scottsdale
These properties are in unincorporated Maricopa County. A standard rural district such as RU-43 (1-acre minimum) allows one single-family home per lot, plus accessory buildings like a garage, workshop or guest house.
The December 2025 update
On December 10, 2025, the Board of Supervisors adopted amendment TA250002 for the Rural-190 and R1-35 districts. Each eligible lot may have one attached and one detached ADU. On lots of an acre or more, a second detached ADU is allowed if at least one unit is deed-restricted for households earning up to 80% of area median income.
Size and placement limits
An ADU can't be larger than the main home; on lots under an acre it's capped at 75% of the main home or 1,000 sq ft, whichever is smaller. Detached ADUs need at least 5 feet from side and rear lines, can be up to 18 feet tall, and all units must share one street access point.
Short-term rentals
If the property has an ADU and is used as a short-term rental, the owner must live on-site (with a narrow exception for ADUs approved before Sept. 13, 2024), and only one rental unit per parcel is allowed at a time.
Check before you plan
Rules vary by district and this change is recent, so confirm the parcel's zoning and ADU eligibility with Maricopa County Planning & Development.