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

Unincorporated Mohave County requires a building permit for construction unless a specific code or ordinance exemption applies¹. Mohave County uses the 2018 International building-code family and 2017 National Electrical Code, with local amendments¹⁰. A detached, one-story storage shed or similar accessory structure is exempt only up to 300 square feet and without utilities; fences and block walls may be exempt up to 7 feet measured from the lowest adjacent property grade⁶. Shipping containers are exempt only for residential storage without utilities, and all other rules and ordinances still apply⁶. Every manufactured-home installation separately requires a building permit⁷. Mohave County allows owner-builders without a licensed contractor, subject to Registrar of Contractors limits; the state exemption requires owner occupancy rather than a project intended for sale, rent, employees or business visitors^8,12. Inside Lake Havasu City, Bullhead City and Kingman, city offices handle building permits^13,14,15. Mohave County Development Services retains delegated septic permitting for conventional and some alternative systems; Bullhead City also controls construction/install permits, with ADEQ or applicable county approval required for private systems serving multifamily, commercial or industrial property^4,16.

The Mohave County Building Division issues building permits and inspections; call 928-757-0903 or visit the county offices at 700 W. Beale Street, Kingman, AZ 86401¹⁷. The Planning & Zoning Division handles zoning classification, zoning permits and code enforcement; email codeenforcement@mohave.gov or call 928-757-0903¹⁸. County Development Services processes permits for conventional and some alternative septic systems under authority delegated by ADEQ; email eqpermits@mohave.gov or call 928-757-0903⁴. For a Floodplain Use Permit, contact the Flood Control District at 928-757-0925, based at 3250 E. Kino Ave., Kingman, AZ 86409¹⁹.

Mohave County zoning governs unincorporated land under the Board of Supervisors’ jurisdiction; ask Planning & Zoning for the parcel’s mapped district, allowable uses and setbacks^2,7. Lake Havasu City, Bullhead City and the Town of Colorado City set their own zoning^20,21,22. County Development Services retains delegated septic permitting for conventional and some alternative systems⁴. Minimum lot sizes include 5 acres in A and 6,000 square feet in R-1; specific ordinance provisions take precedence³. Single-family residential lot coverage, including accessory buildings and storage, cannot exceed 60% except as Section 35 provides; open swimming pools are excluded³.

Unincorporated Mohave County allows an attached and a detached accessory residence where single-family dwellings are permitted, plus another detached residence on lots of at least 1 acre²³. Allowed accessory residences have no size limit on residential lots of at least 5 gross acres; smaller lots require an administrative Accessory Residence Permit up to 75% of the primary home’s size, or a Special Use Permit above that, subject to section requirements²³. A second septic/leach system and water supply require at least 26,500 square feet of lot area, potentially more at Environmental Quality or ADEQ’s direction²³.

A septic project in Mohave County starts with a Notice of Intent to Discharge; construction cannot begin until the county issues a Construction Authorization, and discharge cannot begin until it issues a separate Discharge Authorization⁵. Construction and the request for discharge authorization must be completed within 2 years, and the request must document a passed tank watertightness test; the county then inspects the installation before authorizing discharge⁵. County Development Services processes conventional and some alternative systems under authority delegated by ADEQ⁴. Composting toilets and vault-and-haul systems are listed alternatives, but limiting site conditions can trigger county processing, site investigation, authorization and inspection rather than creating an exemption from sanitation review⁴. Before the site investigation, the sewer provider must complete the Sewer Availability Information Sheet⁵. For a well, file an ADWR Notice of Intent before drilling, deepening or modifying it; domestic wells on 5 acres or less also need local environmental-health review first¹¹. Only 18.7% of Mohave County soils are rated “not very limited” for a conventional drain field; a site evaluation may identify the need for an engineered system, rather than rule out septic²⁴.

An RV is not an unrestricted full-time residence on ordinary residential land: occupancy is capped at 30 cumulative days a year and 14 consecutive days unless a special permit and approved wastewater system apply⁹. Permanent RV residence is limited to an R-RV zone, an RV park or an approved part of a manufactured-home park⁹. A temporary RV residence may be permitted while a permanent home is under construction, and separate renewable permits are available in A-R or R-E zones⁹. Do not assume every tiny home is a park model: Mohave County defines an Appendix Q tiny house as a dwelling of 600 square feet or less excluding lofts, with minimum room dimensions and ceiling heights, but we could not confirm the parcel-level zoning permission for a site-built tiny house; ask Planning & Zoning¹⁰. A park model follows the county's park-model and RV placement rules, including required septic facilities where applicable⁷.

1. Confirm the parcel's zoning classification with the Planning & Zoning Division because it controls allowed uses, lot size and setbacks².
2. Apply through the Building Division's online permitting system; fees vary by project, square footage and sometimes value, and every permit carries a $40 automation fee^8,25.
3. Start work within 180 days of issuance and avoid a suspension or abandonment lasting 180 days²⁵.
4. Have the sewer provider complete the availability form before a septic site investigation, then obtain construction and discharge authorizations as applicable⁵.
5. File a Notice of Intent to Drill with ADWR before well work begins¹¹.
6. Obtain any required county right-of-way and Floodplain Use permits before disturbing the affected land^19,26.
7. Schedule building and septic inspections at the applicable phases^5,27. A manufactured home needs an approved final inspection and Certificate of Occupancy before occupancy, and a structure brought through the Building Amnesty Permit process also needs a Certificate of Occupancy before use^1,28. Ask the Building Division about final approval for other projects because we could not confirm a general countywide rule¹⁷.

About 54.8% of Mohave County land is at a slope of 15% or less, and 71.8% is federal land; verify the parcel's ownership, legal access and usable building area²⁴. In unincorporated Mohave County, work within county-maintained rights-of-way requires a Right-of-Way permit, and changes to land in special flood hazard areas require a Floodplain Use Permit before work begins^19,26. Severe drought occurs in about 29.1% of years, making well feasibility and water storage practical due-diligence items²⁴. A minor land division creating 5 or fewer interests, at least one under 36 acres, without a zoning change requires a Public Works application; the County Surveyor has 30 calendar days for a written determination²⁹. Mohave County's effective property-tax rate is 0.5%, and the median annual bill is $1,229²⁴.