Pinal County supervisors voted to update the county's development code to match a new state law that expands what homeowners can do with accessory dwelling units, often called ADUs.

During the Board of Supervisors meeting on Dec. 10, county staff brought forward a text amendment to the Pinal County Development Services Code, Section 2.150.240. The change renames "guest house and casitas" to "accessory dwelling units" and updates the rules so they line up with Arizona Revised Statutes, including a law passed earlier this year.

Staff explained the update is tied to House Bill 2928, signed May 23, 2025. Under that law, counties have limits on what they can require for ADUs. For example, the county cannot require an ADU to match the exterior design of the main home, cannot require extra parking just because an ADU is added, and cannot require rear or side setbacks greater than five feet.

Staff also told the board the deadline matters. If the county does not adopt the required ADU regulations by Jan. 1, 2026, then ADUs would be allowed on all lots zoned for residential use in the county "without limits," under the state law.

The proposed county rules set the minimum standards required by the state and also include local details that are allowed.

Here are some of the key points discussed:

• A property must have a primary single-family home.
• On lots less than one acre, one attached ADU and one detached ADU would be allowed.
• On lots one acre or larger, one attached ADU and up to two detached ADUs would be allowed.
• Minimum rear and side setbacks would be five feet from the property line. Front setbacks would still follow the rules for the property's zoning.
• Detached ADUs would need to be at least seven feet from the main building.
• Size limits would apply:
  • For lots under one acre: up to 75% of the main home's gross floor area or 1,000 square feet, whichever is less.
  • For lots one acre or larger: up to 75% of the main home's gross floor area or 1,500 square feet, whichever is less.
• ADUs must be at least 200 square feet.
• ADUs must have a separate exterior entrance.
• The ADU and main home cannot have separate utility meters.
• The ADU and main home would not be separately addressed, but the ADU must have a separate unit number so emergency responders can find it.
• ADUs cannot be built on top of a public utility easement unless the homeowner gets written permission from any utility using (or potentially using) the easement.
• Manufactured homes, mobile homes, recreational vehicles, and park model trailers generally cannot be used as ADUs, except in certain situations allowed by state law (including park model trailers on lots three acres or larger in specific zoning situations).
• If a new ADU will use a septic system, the county can require the septic system to be properly sized before construction.

Supervisors asked several practical questions during the discussion, including how crowded multiple units could feel on a single acre, whether ADUs could be rented out, and how parking issues might be handled. Staff noted the county does not regulate or enforce private HOA rules, and HOAs can be more restrictive through their own CC&Rs. Staff also noted that rental use is not specifically restricted in the proposed code language, and enforcement of some issues can be difficult.

One supervisor spoke in favor of ADUs based on personal experience, saying having a second home on a property helped his family care for relatives and made sense for multi-generational living.

When the chair opened the public hearing portion of the item, no one from the public spoke. The board then voted 3-2 to approve the code amendment as presented.

Discussion of Agenda Item #11 starts around 01:25:43