Building permits, zoning and septic rules in Navajo County, Arizona

Unincorporated Navajo County requires a building permit before regulated construction, alterations, occupancy changes, or electrical, gas, mechanical and plumbing work; structures over 200 square feet or with utilities or sleeping quarters require a permit¹. A one-story detached accessory structure at or under 200 square feet can be exempt if it meets setback and fire-separation requirements; interior remodeling costing no more than $1,000 in labor and materials is also listed as exempt¹. Navajo County uses amended versions of the 2018 International Residential Code and International Building Code¹⁰. Arizona's owner-builder licensing exemption applies to work solely for the owner's occupancy, without public business use or an intent to sell or rent; building permits and inspections still apply⁵. Offering the home for sale or rent within one year after completion or a Certificate of Occupancy is prima facie evidence of a sale-or-rent purpose⁵.

Navajo County Planning & Development Services handles building, manufactured-home and delegated septic permits for unincorporated land^3,8,11. Call 928-532-6040 or visit 1100 E. Thornton Rd., Show Low, Monday through Thursday, 6:30 a.m. to 5 p.m¹².. Plan review costs 35% of the building-permit fee, which varies by valuation and formula¹³. Inspections occur at every construction phase, generally with 24 hours' notice; property lines and setbacks must be marked for footing, foundation and septic inspections¹⁴.

Snowflake¹⁵, Holbrook¹⁶, Taylor¹⁷, Pinetop-Lakeside¹⁸ issue their own building permits. Show Low requires a city building permit plus a state installation permit for manufactured homes and factory-built buildings¹⁹. Delegated septic permits remain with county Planning & Development Services; Snowflake requires the county sanitary permit when town sewer is unavailable^3,20.

Navajo County zoning applies to unincorporated land, excluding reservation land outside county authority². Winslow²¹, Snowflake²², Holbrook²³, Taylor²⁴, Pinetop-Lakeside²⁵ administer their own zoning; delegated septic permits remain with county Planning & Development Services³.

A-General generally requires 1 acre, with smaller parcels possible through the specified soils evaluation or approved sewer access; RU-20, RU-10, RU-5 and RU-1 require 20, 10, 5 and 1 acre respectively²⁶. R1-43 and R1-10 require 43,000 and 10,000 square feet respectively²⁶. R-2 and R-3 require 6,000-square-foot parcels, with 2,000 and 1,000 square feet of lot area per dwelling unit respectively²⁶. C-R requires 6,000 square feet per parcel and 1,000 per dwelling unit; these are land-area standards, not dwelling floor areas²⁶. District maps and district-specific setbacks control the parcel^26,27. Qualifying agricultural uses on at least 5 contiguous acres in C-R, Ind-1 and Ind-2 can receive a zoning exemption, which does not remove building, septic, floodplain or health requirements²⁸.

Septic systems within Navajo County's delegated authority go through Planning & Development Services, which acts under a delegation agreement with the Arizona Department of Environmental Quality for systems under 3,000 gallons a day³. You apply with a Notice of Intent to Construct, and once approved you have two years to build; after construction, inspection, and testing, you file a Notice of Intent to Discharge and need a Discharge Authorization before use²⁹. Only about 22.1% of Navajo County's soils lack a severe USDA limitation for a conventional drain field, so the site evaluation can materially shape the system design³⁰. Arizona requires a septic inspection within six months before a property transfer and a buyer's Notice of Transfer within 15 calendar days after closing³¹. Composting toilets and other listed alternatives still require county review and construction and discharge authorization¹⁴. For a well, file a Notice of Intent to Drill with the Arizona Department of Water Resources; domestic wells on parcels of 5 acres or fewer also need county or local-health-authority endorsement⁹.

Outside approved RV parks, unincorporated Navajo County allows a single RV temporarily in A-General, RU, R1 and qualifying Special Development districts; permanent placement and rental use are prohibited⁷. Seasonal RV Permits allow placement once per calendar year for up to 120 days, with a good-cause renewal provision; Temporary RV Permits allow up to one year, renewable for good cause⁷. RVs need permanent power, approved sewage disposal and zoning setbacks plus 10 feet from property lines; generators are prohibited⁷. Stored RVs cannot be used for living, sleeping or housekeeping unless another zoning provision allows it; storage is not an occupancy authorization⁸. Primitive camping on vacant property is a code violation³².

Manufactured homes are allowed dwelling types in A-General and Rural districts, but placement requires a manufactured/mobile-home permit and a stored home cannot be occupied^2,8. We could not confirm a general tiny-home classification; ask Planning & Development Services whether the proposed unit is a site-built dwelling, factory-built building, manufactured home, park model or RV¹².

Where single-family dwellings are allowed in unincorporated Navajo County, lots under 1 acre may have one attached and one detached guest house; lots of at least 1 acre may have one attached and two detached⁸. Guest houses need at least 5 feet of rear and side setback, with front setbacks following the primary dwelling's district⁸. Detached applications require site and preliminary building plans; attached units need no separate guest-house permit, but applicable building, environmental and engineering permits remain⁸. A-General separately lists an Administrative Permit, so ask Planning & Development Services which approvals apply⁸.

RVs and travel trailers cannot serve as guest houses; park models require a permanent or semi-permanent foundation⁸. Arizona also allows qualifying 320–400-square-foot park-model ADUs for single-family residences where zoning specifies one dwelling per three acres or greater, subject to foundation, utility, drainage, wastewater and other zoning requirements; special restrictions apply in high-noise or accident-potential zones³³. Arizona bars county prohibitions on short-term rentals but allows specified health, safety and licensing regulation; we could not confirm Navajo County's local rental application requirements, so ask Planning & Development Services^12,34.

1. Ask Planning & Development Services to confirm county jurisdiction, district, allowed dwelling type and setbacks^2,12,26.
2. Resolve county-road driveway or culvert access with Public Works and obtain a floodplain Development Permit before work in a mapped hazard area^35,36.
3. Obtain septic construction approval and file a well Notice of Intent with Arizona Water Resources if needed; domestic wells on 5 acres or fewer need local endorsement^9,29.
4. Submit construction documents and the building-permit application, then schedule required inspections^6,14.
5. Obtain septic Discharge Authorization before using the system²⁹.

Navajo County receives about 10.8 inches of rain annually and has experienced severe drought in about 41% of years, making a verified water source a priority before buying³⁰. Navajo County's effective property tax rate is about 0.6%, with a median annual bill around $1,126; those figures do not establish a particular parcel's tax bill³⁰. In A-General, a subdivision requires rezoning before approval³⁷. Confirm jurisdiction, district and land-division history with Planning & Development Services before committing to a parcel^2,12,26.