Union County, NM Building Permits, Zoning & Septic Rules

Unincorporated Union County, New Mexico requires state building permits for most residential construction, with the New Mexico Construction Industries Division serving as the permitting authority¹. Septic permits also come from the state, through the New Mexico Environment Department². We could not confirm a current countywide zoning ordinance, so verify parcel-specific land-use limits with Union County before buying or designing a project³.

At a glance

Building permit: Required for most covered work; issued by the New Mexico Construction Industries Division in unincorporated Union County¹⁴
Zoning: Countywide zoning status could not be confirmed; ask Union County about the parcel before relying on a proposed use³
Septic permit: Required before installing or modifying an onsite system; apply through the New Mexico Environment Department²⁵
RV living: Long-term occupancy on private land could not be confirmed; ask Union County before placing or occupying an RV³
Tiny home: A code-compliant tiny house on a permanent foundation is allowed under state rules; local placement rules remain unconfirmed⁶
Manufactured home: A state installation permit and final inspection are required; local placement rules may also apply⁷
Owner-builder: No blanket permit exemption was confirmed; ask CID whether you qualify for a homeowner permit⁸⁹

Who to call

Building permits

New Mexico Construction Industries Division

State building permits and construction-code administration for unincorporated Union County

(505) 476-4700

2550 Cerrillos Road – 3rd Floor, Santa Fe, New Mexico 87505

Septic permits

New Mexico Environment Department Onsite Wastewater Program

Onsite liquid-waste permit applications submitted to the local NMED field office

505-827-2855

Planning & zoning

Union County

Parcel-specific questions about county land use, subdivision status and local requirements

575.374.8896 ext 4

200 Court Street, PO Box 430, Clayton, NM 88415

Contact details are copied from each office’s official page and were checked against it on September 28, 2026.

Do you need a building permit in Union County, New Mexico?

Yes. Most residential construction in unincorporated Union County requires a permit from the New Mexico Construction Industries Division before work begins¹⁴. The statewide residential code covers new construction as well as regulated alterations, repairs, additions, moves, conversions and demolition⁴. Limited exemptions include certain one-story detached storage buildings no larger than 120 square feet, fences no higher than 6 feet and qualifying detached decks no larger than 200 square feet, but separate trade permits may still be necessary⁴. New Mexico applies its amended 2021 residential code to covered homes and accessory structures¹⁰.

Who issues building permits in Union County, and how do you reach them?

The New Mexico Construction Industries Division is the authority for residential permits in Union County's unincorporated areas¹. CID's Santa Fe office is at 2550 Cerrillos Road and can be reached at (505) 476-4700¹¹. Permit fees depend on construction type, square footage, materials and construction cost, so obtain a project-specific amount from CID¹². A complete homeowner package may require any applicable planning or zoning approval, complete plans, the state building application and the fee; CID reports a five-working-day issuance target for complete packages¹³.

Does Union County, New Mexico have zoning?

We could not confirm whether Union County currently applies countywide zoning in unincorporated areas³. New Mexico law permits counties to zone territory outside municipal zoning jurisdiction, but that authority does not prove Union County has adopted an operative zoning ordinance¹⁴. The county does publish a subdivision ordinance, so dividing land is regulated even though the zoning answer remains unresolved¹⁵. Before treating a parcel as suitable for a house, RV, business, agricultural building or second dwelling, ask Union County at 575.374.8896 ext 4 for the parcel's current land-use status and any applicable setbacks¹⁶. Land inside a municipality may be subject to municipal rules rather than county rules¹⁴.

How do septic permits work in Union County?

The New Mexico Environment Department handles onsite liquid-waste permits in Union County, and applications go to the local NMED field office for review¹⁷¹⁸. A permit and fee are required before installing or modifying a covered onsite system, and a dwelling that needs such a system may not be built, altered or moved onto the lot until NMED issues the permit⁵. Only 30.8% of Union County soils are rated without severe limitations for a conventional drain field, so do not assume a standard layout will work before site review¹⁹. NMED can grant, condition or deny the application; call 505-827-2855 to identify the correct field office and application path¹⁷¹⁸.

Can you live in an RV or tiny home on land in Union County?

We could not confirm a Union County rule allowing long-term RV occupancy or temporary camping on private land, so ask Union County about the exact parcel before moving an RV onto it. New Mexico treats a tiny house on a chassis with its permanent axle as an RV subject to RV codes and licensing, while a tiny house placed on a permanent foundation may qualify as a dwelling under the state residential code⁶. A qualifying permanent-foundation tiny house may contain no more than 400 square feet of floor area excluding lofts and must provide complete independent living facilities⁶. State building compliance does not answer unresolved county placement, setback or minimum-lot questions³.

Building a home in Union County: the steps, in order

Ask Union County to confirm the parcel's land-use status, subdivision history and any local setbacks before design³¹⁵.

Confirm the building-permit path with CID and assemble the state application, plans, applicable local approval and fee¹¹³.

Apply to NMED for the septic permit before building or moving a dwelling that will rely on an onsite system⁵.

If access connects directly to a state highway, secure a New Mexico Department of Transportation access permit before constructing or modifying the driveway²⁰.

Schedule required foundation, under-floor or slab, frame, weather-barrier and final inspections; trade finals come before the final general inspection²¹.

What should you check before buying land in Union County?

Start with water and septic feasibility. Union County averages 16.2 inches of precipitation annually, and severe drought has occurred in 46.8% of years²²²³. Because only 30.8% of soils avoid severe conventional drain-field limitations, make the septic site evaluation part of due diligence rather than a post-closing task¹⁹. The terrain is generally gentle, with 91.1% of land at a slope of 15% or less, but parcel-level drainage and flood exposure still matter²⁴. Development in a FEMA Special Flood Hazard Area requires approval from the applicable local floodplain administrator before work begins²⁵. Also confirm legal access, well permitting with the Office of the State Engineer, recorded subdivision status and any municipal jurisdiction before closing¹⁷²⁶.

Watch-outs

Union County's current zoning status, setbacks, minimum home size and long-term RV rules could not be confirmed; ask the county about the specific parcel before purchase or placement³.
A septic permit must be issued before a dwelling that needs an onsite system is built, modified or moved onto the lot⁵.
Direct access to a New Mexico state highway requires a state access permit before the driveway is constructed or modified²⁰.

Sources

Written September 28, 2026 from the rules quoted below, each taken from an official source and re-checked by an independent reviewer. This is research, not legal advice: rules change, so confirm with the office before you buy or build.

How Union County scores

Seclusion91100% ev.

Self-Sufficiency1396% ev.

Admin Boringness4868% ev.

Durability32100% ev.

Property Autonomy38100% ev.

Carry Cost8696% ev.

Evidence strength: 93%. This reports direct-source completeness and fallback use; it is separate from the score and is not a confidence interval. How it works →

$121kTypical home

0.6%Property tax

$852Land / acre

16.2"Annual rain

46.8% of yrsSevere drought

8 / yr (+7.2)Mid-century 100°F days

32 daysMid-century dry spell

1.21" (+2.7%)Mid-century 1-day rain

1.28×Wildfire change factor

100%Forward climate coverage

$2,161Home insurance / yr

2.6% / yrInsurance growth

0.48%Nonrenewal rate

single ZIP shrunk to state medianInsurance basis

50People within 30 min

27,826People within 2 hr

189Radius comparison (15 mi)

1People / sq mi

2.4%Federal land

91.1%Land at 15% slope or less

30.8%Septic soil without severe limits

748,624 acWorkable land screen

5.5%Wooded land

7.1 tonsBiomass / forest ac

52.6°FAvg temp

Answers from the rulebook for Union County

What the ordinances and state agencies actually say — one answer per question, each quoted from the official source and independently re-checked.

Union County rules

Subdividing landRegulated (with conditions)
Subdivision of land in Union County under the county subdivision ordinance.
- The official county ordinances page lists Ordinance 21-1997 as the Subdivision Ordinance.
- The New Mexico State Records Center and Archives identifies Union County Subdivision Regulations adopted by Ordinance No. 21-1997 and filed July 2, 1997.
- The operative ordinance text and any later amendments were not fully extracted.
“Ordinance 21-1997 - Subdivision Ordinance (PDF)”
Ordinances ↗Re-checked Sep 26, 2026

New Mexico rules that apply here

Building permitRequired
Buildings and structures regulated by the New Mexico Residential Code, including residential construction, alterations, repairs, additions, moves, improvements, removals, conversions, and demolitions, and state-administered commercial construction.
- A permit must be obtained before covered work begins.
- Residential exceptions include one-story detached accessory buildings used as tool or storage sheds, playhouses, and similar uses not exceeding 120 square feet; fences not over 6 feet high; specified retaining walls; certain water tanks, sidewalks, driveways, finish work, shallow prefabricated pools, playground equipment, window awnings, and detached decks.
- Unless otherwise exempted, separate plumbing, electrical, and mechanical permits may still be required for otherwise exempted residential work.
- Commercial applicants must be validly licensed with the appropriate license classification, submit the state building permit application, obtain any required city or county zoning approval, and pay the valuation-based fee before permit issuance.
residential accessory-building exemption floor area: <= 120 square feet (One-story detached accessory buildings used as tool and storage sheds, playhouses, and similar uses.) · fence exemption height: <= 6 feet · water-tank exemption capacity: <= 5000 gallons (Height-to-diameter or width ratio must not exceed 2:1.) · detached-deck exemption area: <= 200 square feet (Deck must not be more than 30 inches above grade, must not be attached to a dwelling, and must not serve the required exit door.)
“Except as specified in Section 105.2 IRC, no building or structure regulated by this code shall be erected, constructed, enlarged, altered, repaired, moved, improved, removed, converted, or demolished unless a permit has first been obtained from the building official.”
Building Permit Guide for Residential Construction ↗Re-checked Sep 12, 2026
Building code adoptedAdopted (with conditions)
Commercial construction, alteration, relocation, enlargement, replacement, repair, equipment, use and occupancy, location, removal, and demolition of buildings or structures in New Mexico subject to the jurisdiction of the Construction Industries Division.
- The 2021 New Mexico Commercial Building Code applies on or after July 14, 2023.
- The rule does not apply when performed pursuant to a permit for which an application was received by CID before July 14, 2023.
- Detached one- and two-family dwellings and multiple single-family dwellings (townhouses) not more than three stories high with separate means of egress, and their accessory structures, must comply with the 2021 New Mexico Residential Building Code instead.
- Existing buildings not subject to the residential code undergoing a change of occupancy, repair, alteration, or addition must comply with either the commercial building code or the existing building code, as applicable.
- The rule adopts the 2021 International Building Code by reference, as amended by the rule.
effective date: 2023-07-14 (unless a later date is cited at the end of a section) · adopted reference code: 2021 International Building Code (as amended by 14.7.2 NMAC)
“14.7.2.5 EFFECTIVE DATE: July, 14, 2023, unless a later date is cited at the end of a section. [...] 14.7.2.8 ADOPTION OF THE 2021 INTERNATIONAL BUILDING CODE: A. This rule adopts by reference the 2021 International Building Code, as amended by this rule.”
Rules, Laws, and Building Codes ↗Re-checked Sep 11, 2026
2 more reviewed findings on this topic
- Adopted (with conditions) — Residential construction governed by the New Mexico Construction Industries Division in Union County.
  “2021 New Mexico Commercial & Residential Building Code”
  Building Permit Guide for Residential Construction ↗Re-checked Sep 26, 2026
- Adopted (with conditions) — Detached one- and two-family dwellings, multiple single-family dwellings (townhouses) not more than three stories high with separate means of egress, and their accessory structures in New Mexico subject to the jurisdiction of the Construction Industries Division.
  “14.7.3.5 EFFECTIVE DATE: July 14, 2023, unless a later date is cited at the end of a section. From the date of publication of this rule in the New Mexico register, until December 14, 2023, permits may be issued under either the previously adopted rule, or this rule. After December 14, 2023, permits may be issued only under this rule. [...] A. This rule adopts by reference the 2021 International Residential Code, as amended by this rule.”
  Rules, Laws, and Building Codes ↗Re-checked Sep 11, 2026
InspectionsRequired
State-administered residential and commercial construction requiring building permits.
- Residential inspections include foundation, concrete slab or under-floor, frame, weather-resistive barrier, and final inspection.
- Final electrical, plumbing, and mechanical inspections must occur before the final general construction inspection.
- The building official or Construction Inspector may require additional inspections to establish compliance with the New Mexico Building Code and other enforced laws.
- Inspection requests require the permit number, inspection type, requestor contact information, and confirmation that work is complete and the permit is affixed near the front exterior door.
“REQUIRED INSPECTIONS To request an inspection e-mail us at [email protected] or call 505-222-9813 or 877-243-0979”
Building Permit Guide for Residential Construction ↗Re-checked Sep 12, 2026
Tiny homesAllowed (with conditions)
Tiny houses used as single dwelling units with complete independent living facilities and placed on a permanent foundation statewide in New Mexico.
- The unit must provide permanent provisions for living, sleeping, eating, cooking, and sanitation.
- The tiny house must comply with the New Mexico Residential Code and Appendix AQ.
- Tiny houses constructed in New Mexico or transported into New Mexico must be inspected for compliance with New Mexico Residential Code requirements.
- A tiny house on a chassis with a permanent axle is treated as a recreational vehicle and must meet recreational-vehicle codes and licensing requirements while the axle remains in place.
- If axles are removed and the unit is placed on supports or a foundation, it must comply with the code requirements for tiny houses on a permanent foundation.
- The rule applies to construction, use, and occupancy subject to the jurisdiction of the Construction Industries Division; construction not addressed in the residential code must comply with the New Mexico Commercial Building Code.
maximum floor area excluding lofts: <= 400 square feet (The definition excludes loft area and excludes recreational vehicles.) · minimum habitable-space and hallway ceiling height: >= 6 feet 8 inches (Loft ceiling heights may be lower.) · minimum bathroom, toilet-room, and kitchen ceiling height: >= 6 feet 4 inches (None stated in the cited passage.)
“This appendix shall be applicable to tiny houses used as single dwelling units providing complete independent living facilities for one or more persons”
14.7.3 NMAC — 2021 New Mexico Residential Building Code ↗Re-checked Sep 12, 2026
Manufactured homesAllowed (with conditions)
Installation and resulting residential use and occupancy of new or pre-owned manufactured homes statewide in New Mexico, subject to the Manufactured Housing Division's permitting and inspection rules.
- An installation permit or combined installation and permanent-foundation inspection permit must be obtained before installation.
- The permit must identify the licensees performing installation work and the consumer's name and address; a map is required when the address is a post-office box or rural route.
- An unlicensed homeowner working on the homeowner's own principal residential property must perform the work personally or use division-approved licensees, execute the required acknowledgment, and assume responsibility for applicable federal, state, local, code, and inspection requirements.
- Final inspection must certify that the manufactured home meets the minimum standards for use and occupancy under the act and regulations.
- Permits are valid for 180 days, subject to possible time extension for weather or re-manufacturing or permanent-foundation inspections.
- Each new or pre-owned manufactured home installed in New Mexico requires an installation permit.
- Failure to obtain a permit subjects the homeowner, dealer, or installer to a fine of double the permit fee.
- Local requirements, codes, and inspections still apply; the cited state rule does not establish local land-use placement or zoning permission.
installation permit validity: 180 days (A time extension may be granted for weather-related delay or inspections involving a home being re-manufactured or installed on a permanent foundation.) · permit for certain alteration, modification, or repair: 15 USD (Available upon written request and excludes warranty work performed under a previous permit and installation.) · fine for installation without permit: double the permit fee (Applies to the homeowner, dealer, or installer.)
“inspectors shall certify on the permit, or upon any inspection report, that the manufactured home meets the minimum standards for use and occupancy”
14.12.9 NMAC — Inspections ↗Re-checked Sep 12, 2026
Who permits septicState
Onsite wastewater and liquid-waste permitting in Union County.
- Applications are submitted to the local NMED field office.
- NMED may grant, condition, or deny the permit.
- The Office of the State Engineer handles well-drilling permits and related well information.
“Submit to Local NMED Field Office for review”
Apply for a Permit ↗Re-checked Sep 26, 2026
One more reviewed finding on this topic
- State — On-site liquid waste systems and effluent receiving 5,000 gallons or less per day and not requiring a discharge plan or NPDES permit.
  “20.7.3.1 ISSUING AGENCY: New Mexico Environmental Improvement Board.”
  20.7.3 NMAC — Liquid Waste Disposal and Treatment ↗Re-checked Sep 12, 2026
Septic permitRequired
Installation or modification of a new or existing on-site liquid waste system, including residential or commercial units on lots for which such a system is required.
- A permit issued by the New Mexico Environment Department, including payment of the permit fee, is required before construction or modification.
- A permit is not required for graywater discharges or systems meeting 20.7.3.810 NMAC.
- A dwelling may not be constructed, modified, or transported onto a lot requiring an on-site liquid waste system unless the department has issued the permit beforehand.
- Other state, city, county, or federal approvals may also be required.
- The department generally acts within 10 working days after a completed conventional-system application, subject to the rule's extension for potentially more stringent requirements.
maximum regulated flow: <= 5000 gallons per day (20.7.3.2 NMAC scope limitation) · permit application completeness determination: 5 working days (Conventional systems) · conventional permit decision: 10 working days (After receipt of a completed application; review may extend to 20 working days when more stringent requirements may be necessary)
“No person shall install or have installed a new on-site liquid waste system or modify or have modified an existing on-site liquid waste system, unless that person obtains a permit issued by the department, including payment of the permit fee, prior to construction of such installation or modification.”
20.7.3.401 NMAC — Permitting; General Requirements ↗Re-checked Sep 12, 2026
Off-grid sanitationLimited
Privies, permitted on-site liquid waste systems, and qualifying private residential graywater discharges statewide.
- A privy may dispose of human excreta and toilet paper but not other liquid wastes.
- Untreated liquid waste must go to a permitted and approved enclosed system, permitted and approved treatment unit, or public sewer, except qualifying graywater.
- Graywater under 250 gallons per day may be used for household gardening, composting, or landscaping irrigation only if all listed conditions are met, including no runoff, no spraying, no watercourse discharge, floodway exclusion, five-foot groundwater separation, local ordinance compliance, 24-hour storage limit, and specified well setbacks.
- Graywater use for purposes other than irrigation or composting requires a department permit.
private residential graywater discharge: < 250 gallons per day (Qualifying graywater discharge under 20.7.3.810 NMAC) · graywater setback from private domestic well: >= 100 feet · graywater setback from public water supply well: >= 200 feet · graywater storage before discharge: <= 24 hours
“A privy may be used for the disposal of human excreta and toilet paper, but not for the disposal of other liquid wastes.”
20.7.3 NMAC — Liquid Waste Disposal and Treatment ↗Re-checked Sep 12, 2026
Mandatory utility hookupConditional
Residential and commercial units using an on-site liquid waste system when a public sewer is available and connection is required by the local authority with jurisdiction.
- A public sewer is deemed available when it has capacity and is located in a thoroughfare, right-of-way, or easement abutting the lot.
- The on-site system must be properly abandoned within 30 days after connection.
- The state rule does not itself identify which local authority will require connection.
abandonment deadline after sewer connection: 30 days
“All residential and commercial units utilizing an on-site liquid waste system shall connect to a public sewer upon availability and if required in accordance with the local authority that has jurisdiction.”
20.7.3 NMAC — Liquid Waste Disposal and Treatment ↗Re-checked Sep 12, 2026
Agricultural exemptionConditional
Statewide agricultural exemption from the New Mexico Subdivision Act for the sale, lease, or other conveyance of a parcel of at least 35 acres.
- The parcel must be thirty-five acres or larger.
- The conveyance must occur within a twelve-month period covered by the statutory exception.
- The land must have been used primarily and continuously for agricultural purposes, in accordance with Section 7-36-20 NMSA 1978, for the preceding three years.
minimum parcel size: >= 35 acres · agricultural use duration: >= 3 years (land must have been used primarily and continuously for agricultural purposes in accordance with Section 7-36-20 NMSA 1978) · conveyance period: 12 months (within any twelve-month period)
“the sale, lease or other conveyance of any parcel that is thirty-five acres or larger in size within any twelve-month period; provided that the land has been used primarily and continuously for agricultural purposes, in accordance with Section 7-36-20 NMSA 1978, for the preceding three years;”
Senate Bill 176 — New Mexico Subdivision Act ↗Re-checked Sep 12, 2026
Driveway accessRequired
Permanent or temporary direct vehicular access from property in close proximity to or adjoining a New Mexico state highway.
- An access permit must be issued by the New Mexico Department of Transportation before constructing or modifying covered access.
- Access permits are issued only when the application complies with 18.31.6 NMAC.
- The department or an approved issuing authority may impose terms and conditions.
- The rule concerns state highways under the jurisdiction of the state transportation commission; it does not establish a universal permit requirement for every non-state roadway.
- For additional traffic from expansion or redevelopment, the property owner must contact the department to determine whether a new application or access modification is required; no new application is required if the department determines modifications are unnecessary.
“no person shall construct or modify any permanent or temporary access [...] without an access permit issued by the New Mexico department of transportation.”
18.31.6 NMAC ↗Re-checked Sep 12, 2026
Building in a floodplainRequired
Construction or development within a FEMA Special Flood Hazard Area in a New Mexico community, and proposed construction or other development in communities where FEMA has not defined a Special Flood Hazard Area.
- Approval by the local community Floodplain Administrator is required before construction or development within any Special Flood Hazard Area.
- Where FEMA has not defined the Special Flood Hazard Area, the community must require permits for all proposed construction or other development, including manufactured homes, to determine whether the activity is in a flood-prone area.
- Approval is intended to ensure compliance with the National Flood Insurance Program and the community’s floodplain management ordinance.
- The source identifies 104 New Mexico communities participating in the National Flood Insurance Program; the administering official is the applicable local community Floodplain Administrator, not the state agency.
“Approval by the local community Floodplain Administrator is required before construction or development begins within any Special Flood Hazard Area.”
Flooding ↗Re-checked Sep 12, 2026
Permit feesPublished (with conditions)
New Mexico CID building-permit fees applicable to construction in Union County.
- General building permitting fees depend on construction type, square footage, materials, and construction costs.
- Applicants are directed to contact CID offices for the applicable fee.
- The page lists separate electrical, plumbing, LP-gas, and inspection fee schedules.
“Permitting Fees are based upon type of construction, square footage, type of materials and construction costs.”
Construction Industries Forms and Applications Fees ↗Re-checked Sep 26, 2026
One more reviewed finding on this topic
- Variable (with conditions) — New Mexico Construction Industries Division permitting fees for covered construction work statewide.
  “Permitting Fees are based upon type of construction, square footage, type of materials and construction costs.”
  Construction Industries Forms and Applications Fees ↗Re-checked Sep 12, 2026
Permit processPublished (with conditions)
CID residential building-permit process applicable to construction in Union County.
- Homeowner applications require planning and zoning approval when applicable, two complete sets of plans, the Multi-Purpose State Building Application, and payment of the building permit fee.
- CID states that complete packages are reviewed and a building permit issued within five working days; residential permits are generally processed in three to four working days.
- Zoning approval, incomplete information, or missing professional stamps may delay processing.
complete-package issuance target: 5 working days · residential processing time: 3 to 4 working days
“issue a building permit within five (5) working days”
Construction Industries Division Frequently Asked Questions ↗Re-checked Sep 26, 2026
One more reviewed finding on this topic
- Published (with conditions) — Construction Industries Division permit applications in New Mexico.
  “Permits can also be completed using our online permitting portal.”
  Forms and Applications ↗Re-checked Sep 12, 2026
county zoning authorityGeneral
New Mexico counties may adopt zoning ordinances for all or any portion of county territory that is not within a municipality's zoning jurisdiction.
- The county zoning authority's ordinance applies only to territory not within the zoning jurisdiction of a municipality.
- Municipalities may have concurrent extraterritorial zoning authority in specified circumstances, including population-based distances, overlapping extraterritorial jurisdictions, and additional territory placed under municipal jurisdiction by county-municipal agreement.
- Concurrent municipal authority is exercised pursuant to an extraterritorial zoning authority or joint powers agreement and may be exercised whether or not the county has enacted a comprehensive zoning ordinance.
- In the absence of a county zoning ordinance, a qualified-elector petition signed by at least twenty-five percent of votes cast for governor at the preceding general election may require the board of county commissioners to adopt a county zoning ordinance within one year.
“A. a county zoning authority may adopt a zoning ordinance applicable to all or any portion of the territory within the county that is not within the zoning jurisdiction of a municipality;”
Senate Bill 241, Final Version ↗Re-checked Sep 21, 2026
county building authorityLimited
New Mexico counties that qualify as an authority having jurisdiction may administer permitting, inspection, and enforcement for residential construction in unincorporated areas and enforce applicable New Mexico construction codes.
- A county must have a full-service building department employing a full-time certified building official and have permitting, inspection, and enforcement authority over general construction, electrical, and mechanical-plumbing trades.
- A county established as an authority having jurisdiction before July 1, 2009 may continue with authority over specified trades without a full-service building department until it relinquishes that authority.
- Construction work subject to the Construction Industries Licensing Act and applicable rules requires the applicable permit before construction or specified installation, alteration, repair, maintenance, or demolition work begins, unless an applicable statute or rule provides otherwise.
- The statewide rule is effective March 10, 2022, unless a later date is cited at the end of a section.
- A permit may be issued to a homeowner only subject to the limitations of 14.5.2.18 NMAC and an annual permit under 14.5.2.19 NMAC.
““Authority having jurisdiction” “AHJ” means the state or a municipality, county or other political subdivision that has a full-service building department employing a full-time certified building official and has permitting, inspection and enforcement authority over the general construction, electrical and mechanical-plumbing trades within its jurisdiction.”
14.5.1 NMAC, Construction Industries General Provisions ↗Re-checked Sep 21, 2026

Still unanswered

We looked and could not find an official answer yet. Silence is not permission — ask the county directly.

County-wide zoning — Countywide zoning authority in Union County, including unincorporated areas.
Local zoning — Local zoning in Union County; the official materials reviewed did not establish a current county, municipal, or other local zoning rule.
Zoning districts — Published zoning districts in Union County.
Minimum dwelling size — Minimum dwelling size in Union County.
Minimum lot size — Minimum lot size in Union County.

8 more unanswered

Setbacks
Lot coverage
Building height
Living in an RV
Camping on your land
Accessory dwellings
Well permit
Short-term rentals

Each answer was extracted from an official source and independently re-checked against that source by a second reviewer. That is an evidence check, not legal advice. Rules change; confirm with the authority before you buy or build.

Water rights & wells in Union County

Whether a new home can legally get its own water here — the sub-state groundwater regime, from New Mexico’s water agency.

Actively managed

This basin is under active state management — new water use is scrutinized, though a domestic well is usually still allowed.

Household wellPermit required (issued by right)

Nearly all developed New Mexico lies inside an OSE 'declared' underground water basin, but a household 72-12-1.1 domestic well is a by-right permit the State Engineer issues even in closed/over-appropriated basins (metering can be required). The by-right amount is cut to 0.25 acre-ft/yr in a declared Domestic Well Management Area, and a few basin-specific orders cap it further (Gallup Order 197, Zuni Order 199) or stop issuing new domestic permits entirely (Hot Springs Order 198).

Limit: 1 acre-ft/yr by right (NMSA 72-12-1.1); 0.25 acre-ft/yr in a declared Domestic Well Management Area

NM OSE domestic well rules, 19.27.5 NMAC ↗

Tucumcari Underground Water Basinpartial of county
OSE-declared Article-7 groundwater basin; new non-domestic (72-12-3) appropriations require an OSE permit showing unappropriated water. The 72-12-1.1 household domestic well remains by-right — no Domestic Well Management Area is declared in New Mexico. OSE-declared basin centered on Quay County (Order 155, 1998).
NM OSE Article 7 (Declared Underground Water Basins) ↗
Clayton Underground Water Basin (Eastern portion)partial of county
OSE-declared Article-7 groundwater basin; new non-domestic (72-12-3) appropriations require an OSE permit showing unappropriated water. The 72-12-1.1 household domestic well remains by-right — no Domestic Well Management Area is declared in New Mexico. OSE 2019 guidelines apply block administration to the thin (<50 ft) Ogallala/High Plains aquifer; guidelines expressly exempt 72-12-1.1 domestic wells.
NM OSE Eastern Clayton Basin Guidelines (2019) ↗

Prior-appropriation state (first in time, first in right). Groundwater rules change and basin boundaries follow the aquifer, not the county line — confirm current well and appropriation rules with the New Mexico state water agency before you buy or drill.Groundwater governance as of Jul 2026, cited to each administering agency.

Living off-grid in Union County, New Mexico

Is Union County a good place to live off-grid or homestead?

Union County scores 35/100 on the Bolthole Index, a marginal county profile. Its strengths: deep seclusion — about 50 people within a 30-minute drive and manageable long-term carry cost. Watch-outs: thin water margin (16.2″/yr rainfall) and elevated current hazard exposure.

Do you need a building permit in Union County, New Mexico?

Union County generally requires a residential building permit. Onsite septic is permitted by New Mexico Environment Department - Onsite Wastewater (Liquid Waste) Bureau. These answers are quoted from official sources and independently re-checked. Rules change and cities within the county differ — always confirm with the county before you buy or build.

How much does land cost in Union County, New Mexico?

Land in Union County runs about $852 per acre, based on the latest county data.

What is the water situation in Union County?

Union County gets about 16.2" of rain a year, with severe drought in roughly 46.8% of years. On water rights, Union County lies in the Tucumcari Underground Water Basin — OSE-declared Article-7 groundwater basin; new non-domestic (72-12-3) appropriations require an OSE permit showing unappropriated water. The 72-12-1.1 household domestic well remains by-right — no Domestic Well Management Area is declared in New Mexico. OSE-declared basin centered on Quay County (Order 155, 1998)..

How remote is Union County?

A representative private-land location has about 50 people within a 30-minute drive and 27,826 within two hours. The road-network catchments count population across county lines and clusters of smaller cities; straight-line radius values remain available as a comparison.

Building permits, zoning and land rules in Union County, New Mexico

At a glance

Who to call

Do you need a building permit in Union County, New Mexico?

Who issues building permits in Union County, and how do you reach them?

Does Union County, New Mexico have zoning?

How do septic permits work in Union County?

Can you live in an RV or tiny home on land in Union County?

Building a home in Union County: the steps, in order

What should you check before buying land in Union County?

Watch-outs

Sources

Union County in New Mexico

How Union County scores

Find land. Bring the promising ones back.

Parcel due diligence

Answers from the rulebook for Union County

Union County rules

New Mexico rules that apply here

Still unanswered

Water rights & wells in Union County

Living off-grid in Union County, New Mexico

Is Union County a good place to live off-grid or homestead?

Do you need a building permit in Union County, New Mexico?

How much does land cost in Union County, New Mexico?

What is the water situation in Union County?

How remote is Union County?

How Union compares in New Mexico