DISCLAIMER: Before beginning any construction or making changes, property owners should review current regulations and obtain all required approvals from the appropriate government department.
Pinal County supervisors approved expanded accessory dwelling unit regulations on December 10, 2025. The new rules, which take effect 30 days after adoption, allow multiple ADUs per residential lot and reduce setback requirements. The changes bring local code into compliance with state law before a January 2026 deadline.
The 4-1 vote marks the final step in a months-long process to update county development code. The ordinance expands what property owners can build.
What Residents Can Build Under the New Rules
The approved regulations allow different numbers of ADUs based on lot size.
For lots less than one acre, property owners may build one attached ADU plus one detached ADU. For lots one acre or larger, owners may add one attached ADU and up to two detached units. All properties must have a single-family dwelling as the primary residence before any ADU construction begins.
Size limits apply to all accessory dwelling units. On lots under one acre, ADUs cannot exceed 75% of the primary home’s floor area or 1,000 square feet, whichever is less. Larger lots of one acre or more allow ADUs up to 75% of the primary dwelling or 1,500 square feet, whichever is less. All ADUs must be at least 200 square feet.
ADUs must be at least five feet from rear and side property lines. Front setbacks must match those required for single-family homes in the same zoning district. Detached ADUs must sit at least seven feet from the main building.
State Law Limits County Options
State law sets a floor that the county cannot go below. County Manager Leo Lew sought clarification on this point during the meeting. He asked Interim Associate Public Works Director Dedrick Denton whether the permitted uses—one attached, one detached under one acre, and one attached, two detached over an acre—”are minimums that are also required out of state statute.” Denton confirmed they were. Lew then asked whether supervisors “have discretion to go more than, but they do not have discretion to go less than.” Denton again confirmed.
This limitation became clear when Vice Chairman Jeff McClure initially asked about restricting additional ADUs to properties of two acres or more. “It’s a bit crowded on an acre,” McClure said. “I think ‘Wow, that’d be a lot of homes on that.’ Can we go to two acres?” Staff confirmed that making the rules more restrictive than state minimums was not an option.
Governor Katie Hobbs signed House Bill 2928 on May 23, 2025. The law requires all Arizona counties to adopt ADU regulations by January 1, 2026. If a county misses the deadline, ADUs will be allowed on all residential lots without limits.
Supervisors Raise Questions About Rentals, Construction Types
Several supervisors sought clarification on specific scenarios residents might encounter.
Supervisor Jeff Serdy asked about rental restrictions. “So these are not rentals, right?” he said. “These cannot be used as a money maker to alleviate the hordes of apartments that are being approved. These are only for family or visitors with no profit to be made. Is that correct or is that written into this?”
Denton said rental restrictions are not in the ordinance. “We don’t get into the rental business,” he said. In fact, state law protects the right to rent ADUs long-term, defined as leases of 90 days or longer or month-to-month arrangements. The statute does not address short-term rentals.
Chairman Stephen Miller asked about the definition of an attached ADU. “An attached accessory dwelling unit—it would be like an addition to a house—but does it have to have a separate entrance and a separate exit?” Denton confirmed that attached ADUs must have their own exterior door. An attached ADU may share a wall with the main dwelling but cannot rely solely on an interior hallway connection.
Supervisor Mike Goodman questioned what types of structures qualify. “Can they take a storage unit, a portable storage unit, and turn it into a detached living facility?” Denton explained that such conversions depend on passing building inspections and meeting zoning requirements for the specific location.
Despite limited local control, Chairman Miller expressed support for the concept. “I think the legislature’s heard there’s a need and a want for this by the public,” he said. “I think it oughta be allowed at some level.”
Supervisor Rich Vitiello, who cast the lone dissenting vote, offered a different view. “This is just to add to their verbiage of affordable housing,” he said, expressing concern about state involvement in local planning decisions.
HOA Communities Face Different Rules
Homeowners in communities with HOAs may face additional restrictions beyond county regulations. Denton noted that “the county does not enforce the CC&Rs because those are private agreements between the homeowners and then the HOA.”
This means HOA communities can impose their own restrictions on accessory dwelling units through their covenants, conditions, and restrictions. The ordinance allows ADUs throughout unincorporated Pinal County, but individual HOAs retain authority to further restrict them within their communities.
Residents considering an ADU project should review their HOA documents before beginning any planning or construction.
Additional Requirements for Property Owners
Beyond size and setback rules, the ordinance includes several other provisions.
All ADUs must share the same street access as the primary dwelling. Property owners cannot install separate utility meters for ADUs. Each ADU must have a separate exterior entrance but shares the property’s address, with a distinct unit number for emergency response.
Manufactured homes, mobile homes, and recreational vehicles cannot serve as ADUs. However, A.R.S. § 11-820.03 allows park model trailers as ADUs on properties zoned for one dwelling unit per three acres or greater.
Construction cannot occur on current or planned public utility easements without written consent from utilities currently using or potentially using the easement in the future. Applicable building codes, fire codes, and other safety and environmental regulations still apply. However, the county cannot require ADUs to comply with commercial building codes or contain fire sprinklers.
If a new ADU will not connect to a sewer system, or if the existing sewer system lacks capacity, the county will require an adequately sized septic system before construction begins.
The ADU regulations do not apply to properties on tribal land, near military airports or ancillary military facilities, in high noise or accident potential zones, or near certain commercial and general aviation airports. Residents near airports should review the ordinance or contact the county for specific exemption criteria.
Path to Approval Spanned Several Months
The county began working toward these changes after HB 2928 became law. Staff held a public open house on November 3, 2025, though no members of the public attended that session.
The Board of Supervisors discussed the proposed changes during a work session on November 12, 2025. At that meeting, officials walked through the draft regulations and answered initial questions from board members.
The Planning and Zoning Commission held a public hearing on November 20, 2025. Commissioners recommended approval unanimously, voting 9-0 with no stipulations. The Board of Supervisors held the final public hearing on December 10, 2025. No members of the public spoke for or against the ordinance.
The county also updated its ADU rules in 2024, when the Board of Supervisors removed prohibitions on kitchen facilities and rental agreements for guest houses and casitas. That earlier change laid groundwork for the current, more comprehensive update.
When the Rules Take Effect
The ordinance takes effect 30 days after its December 10 adoption. Property owners in unincorporated Pinal County can then build ADUs under the expanded regulations.
Residents should contact their local planning department to verify current regulations before starting any construction.
