Cochise County adopts countywide rules for accessory dwelling units to align with state law

The Cochise County Board of Supervisors voted 3-0 on Sept. 2 to adopt zoning ordinance 25-18, a county-initiated text amendment that revises definitions and use standards for accessory dwelling units (ADUs) to conform with new state law (House Bill 2928).

The change allows ADUs "on any lot where a single family dwelling is permitted," expands the number of permitted units in several districts and sets maximum size and setback limits, county staff said. Miss McLaughlin, the county staff presenter, told the board that the ordinance "will expand flexibility, increase housing capacity, and bring our code into alignment with Arizona's recent ADU legislation," and cited ARS and HB 2928 as the enabling state law.

The amendment sets several limits: on each lot with a single-family home, one attached and one detached ADU are permitted; parcels of at least 1 acre may add one additional detached ADU; an ADU may be up to 75% of the size of the principal structure or 1,000 square feet, whichever is less; and ADUs must have no less than a 5-foot setback from property lines. The text also removes a local rental restriction, allows certain park-model RVs as ADUs on larger parcels and changes some review pathways so deviations (for example, to exceed the size cap) go to the Planning and Zoning Commission rather than the Board of Adjustment.

Miss McLaughlin told the board that the Planning and Zoning Commission recommended approval by a 6–1 vote after one public speaker supported the changes at the commission hearing. She also warned that "if a county fails to adopt development regulations as required by the section on or before 01/01/2026, accessory dwelling units shall be allowed on all lots or parcels zoned for residential use in the county without limits," a provision she said is in the state statute.

Opposition and concerns came from the chair of the Planning and Zoning Commission, Miss DePuy, who described the changes in pointed terms and warned of neighborhood impacts. DePuy told the board, "Accessory dwelling unit revisions were sold by lobbyists as affordable housing for the homeless and middle income folks. It's baloney. It benefits landlords who have money to invest in backyard casitas." She said the change removes local guardrails and predicted effects such as higher local property taxes and increased parking and driveway pressure.

Board members debated the trade-off between adopting a locally controlled ordinance that imposes limits and letting the statutory deadline pass, which, they were told, would leave the county without local restrictions. One supervisor summarized the choice as "some control versus no control." Several supervisors said they would contact Cochise County legislators to seek amendments to the state law in the future.

The ordinance was adopted on a 3–0 vote. The board recorded the adoption as the county's effort to retain local zoning authority while complying with state ADU requirements.

The county staff presentation listed technical changes (unit counts, size caps, setbacks, allowed accessory uses and altered review pathways) and noted that the amendment affects seven zoning districts where single-family dwellings are permitted. The board and staff repeatedly framed the action as a protective step to preserve as much local control as state law allows.

Miss McLaughlin and Planning and Zoning staff said the new rules permit multiple mailboxes and certain small park-model units on larger lots (subject to district requirements) and that use deviations exceeding the stated maxima would require Planning and Zoning review.