Building permits, zoning and septic rules in San Juan County, New Mexico

Yes: unincorporated San Juan County requires a building permit for a home, issued by the county Building Department, and the permit will not issue without a verified E-911 physical address¹. The county lists the 2021 New Mexico Residential Building Code and the 2021 International Residential Code among its applicable codes⁹. New Mexico requires a permit before covered residential construction begins; listed exceptions include a one-story tool or storage building no larger than 120 square feet, although separate plumbing, electrical or mechanical permits may still apply¹⁰. The residential permit fee covers required inspections, which the local authority having jurisdiction administers¹⁰. County-covered new homes, additions and accessory structures require at least 24 hours' notice for an inspection request¹¹. Inside Farmington, the city handles building permits for most residential projects; Bloomfield requires its own mobile-home movers/set permit before moving a mobile home for occupancy^12,13. Septic permitting remains with NMED, including inside Bloomfield^4,14.

The San Juan County Building Department, part of Community Development, handles building permits for unincorporated San Juan County, while septic permits stay with the state Environment Department^1,4. Reach the office at (505) 334-4313; the county's main address is 100 South Oliver, Aztec, NM 87410¹. The county page also lists rural addressing at (505) 334-4314, land divisions at (505) 334-4248, floodplain and mobile-home permits at (505) 334-4719, county-road driveway permits at (505) 334-4530, and state or U.S. highway driveway permits at (505) 476-4223¹. For a county building-permit fee quote, contact the San Juan County Building Department at (505) 334-4313¹. A building or structure covered by the county residential checklist cannot be used or occupied until the building official issues the required certificate¹¹.

Rural, unincorporated San Juan County has no county zoning requirements; the county checklist requires planning/zoning approvals in Aztec, Bloomfield and Kirtland^2,3. Farmington and Bloomfield each administer their own zoning, while NMED remains the septic authority^4,15,16. County zoning sets no minimum lot size or dwelling size on rural unincorporated parcels, but building-code and sewage-disposal requirements remain applicable^2,3. San Juan County Building Division design criteria specify 10-foot side and rear setbacks and a 25-foot front setback for covered residential construction; these are building-design criteria, and municipal zoning or floodplain approval may also apply². The county ordinance list includes Farmington extraterritorial zoning, so ask the Building Department which jurisdiction covers the parcel^1,2.

The New Mexico Environment Department handles septic permit decisions for San Juan County through its local field office⁴. Installing or modifying a system requires an application with ownership proof, a site diagram, bedroom count and supporting site information; payment follows approval or conditional approval⁴. NMED lists up to 5 business days for a conventional-system completeness check and 10 business days for a decision; advanced-treatment applications may take up to 10 and 20 business days respectively, and incomplete applications can delay processing⁴. Septic fees vary by system type and design flow⁴. Request inspection 48 hours ahead, leave the system uncovered, and obtain the Permit to Operate after approval; homeowner installations also require final NMED inspection⁴. Subdivision lots using individual systems need at least 0.75 acre of net area; community-service availability, prohibitive soils and state septic setbacks can also prevent installation⁸. About 22.5% of county soils lack severe conventional-drain-field limitations, so evaluate the site early¹⁷. Call the Farmington Field Office at 505-566-9741¹⁸.

In rural, unincorporated San Juan County, no county zoning rule restricts living in an RV, camping temporarily, placing a manufactured home or building an accessory dwelling, because the county has no zoning ordinance there³. That answer covers zoning only: a home still needs a building permit and an E-911 address¹, septic needs New Mexico Environment Department approval⁴, and a manufactured home needs a state installation permit⁷. The rural zoning answer does not apply to municipal land; Aztec, Bloomfield and Kirtland require planning/zoning approvals³. New Mexico allows a tiny house as a dwelling when it is on a permanent foundation, contains complete living facilities and complies with the state residential code; its floor area may be no more than 400 square feet excluding lofts⁵. A tiny house on a chassis with a permanent axle is treated as a recreational vehicle while the axle remains in place⁵. Operating tiny homes within a county-regulated manufactured-home or recreational-vehicle park requires a park license, plumbing and electrical permits, address and floodplain review, water approval and written NMED wastewater approval⁶.

1. Get a verified E-911 physical address; San Juan County will not issue the building permit without one¹.
2. Confirm the parcel's jurisdiction, because unincorporated areas lack county zoning while municipal zoning applies in Aztec, Bloomfield and Kirtland³.
3. Check the site plan against the county's 10-foot side and rear design setbacks and 25-foot front design setback, plus any stricter rule that applies to the parcel².
4. If the project divides land for sale, lease, conveyance or development, obtain county subdivision approval or an approved exemption before proceeding⁸.
5. Submit ownership proof, a site diagram, bedroom count and supporting site information to the NMED Farmington Field Office for the septic permit^4,18.
6. Prepare the owner, location, legal description, work description, materials and square footage for the building-permit application; ask the county Building Department which plans it requires, since the state guide describes a state application^1,10.
7. Schedule county inspections with at least 24 hours' notice, and request NMED's septic inspection 48 hours, or 2 business days, ahead without covering the system^4,11.

San Juan County receives about 8.9 inches of precipitation a year and has spent roughly 50.7% of years in severe drought, so verify a lawful, dependable water source before closing¹⁷. Only about 22.5% of county soils lack severe limits for a conventional septic drain field, making early site evaluation especially useful¹⁷. About 25.2% of the county is federal land, so check parcel boundaries and legal access rather than assuming neighboring open ground is usable¹⁷. A land division into two or more parcels for sale, lease, conveyance or building development requires county approval or an approved exemption outside municipal boundaries, except within the Navajo Nation reservation boundaries⁸. The effective property-tax rate is about 0.7%, with a median annual bill near $1,249¹⁷.