ADU rules in Coconino County, AZ — also called accessory dwelling unit regulations or granny flat ordinances — cover setbacks, owner-occupancy, parking, and permit requirements.
Under Arizona HB 2928 (A.R.S. §11-810.01), Coconino County must allow at least one attached and one detached accessory dwelling unit on any single-family lot, plus a third detached unit on parcels of one acre or more.
HB 2928, signed in May 2025, extended Arizona's ADU mandate to counties through A.R.S. §11-810.01, and the Coconino County Board of Supervisors updated its zoning ordinance in 2025 to comply by the January 1, 2026 deadline. On any lot where a single-family dwelling is allowed, owners may build one attached and one detached accessory dwelling; parcels one acre or larger get a third detached unit. Each unit may be up to 75 percent of the main home's floor area or 1,000 square feet, whichever is less. Mobile homes are not allowed as accessory dwellings. Flagstaff, with over 75,000 residents, follows the parallel municipal law, A.R.S. §9-461.18 (HB 2720).
Building or occupying an accessory dwelling without a building permit is a code violation subject to stop-work orders and after-the-fact permitting. A unit over the size cap is non-compliant.
Other ordinances people look up for this city. Green dot = verified primary-source excerpt.
Coconino County, AZ
Coconino County may require hosts to carry liability insurance for short-term rental properties. Minimum coverage amounts vary by jurisdiction.
Coconino County, AZ
Coconino County limits the number of guests allowed in short-term rental properties. Occupancy caps are typically based on bedroom count or square footage to...
Coconino County, AZ
Neither Arizona nor Coconino County regulates holiday decorations. No permit is needed for lights, inflatables, or yard displays on your own property. The re...
Coconino County, AZ
Temporary garage- and yard-sale signs are allowed on private property during the sale, but only for a short window and only with the owner's permission. Sign...
Coconino County, AZ
Arizona strongly protects political signs. A.R.S. §16-1019 lets you place them in the public right-of-way from 71 days before an election through 15 days aft...
Coconino County, AZ
Arizona requires every residential rental owner to register the property with the county assessor under A.R.S. §33-1902. In Coconino County you file owner an...
See how Coconino County's adu rules rules stack up against other locations.
Help us keep this page accurate. If you notice an error or outdated information, let us know.