Doña Ana County, NM Building Permits, Zoning & Septic Rules

Doña Ana County, New Mexico requires a building permit for residential construction in unincorporated areas, administered by the county's Building Services Division¹. The county also has zoning countywide under its Unified Development Code, which Community Development monitors alongside the county's comprehensive plan². Septic systems are a state matter here: the New Mexico Environment Department, not the county, issues onsite liquid-waste permits, and Doña Ana County residents apply through NMED's Las Cruces field office³. We could not confirm whether Doña Ana County recognizes an owner-builder exemption; New Mexico's own rule only allows a homeowner permit under limited conditions, so ask Building Services directly⁴⁵.

At a glance

Building permit: Required in unincorporated Doña Ana County, issued by Building Services¹
Zoning: Yes, countywide, under the Unified Development Code²
Septic permit: State permit through NMED's Liquid Waste Program, not the county³
Owner-builder exemption: Not confirmed at the county level; New Mexico limits homeowner permits by rule⁴
Tiny home on a foundation: Allowed up to 400 sq ft (excluding lofts) under the state residential code⁶
Agricultural land-sale exemption: Parcels of 35 acres or more used for farming can skip the state Subdivision Act⁷
Minor accessory structure: No permit needed for a one-story shed, playhouse, etc. up to 120 sq ft statewide⁸

Who to call

Building permits

Doña Ana County Building Services Division

Building, plumbing, mechanical, electrical and manufactured (mobile) home permitting, plan review, and inspection for unincorporated Doña Ana County

(575) 647-7350

[email protected]

845 N Motel Blvd, Las Cruces, NM 88007

Zoning

Doña Ana County Community Development

The county's Comprehensive Plan, the Unified Development Code (zoning), the county map atlas, GIS and rural addressing for Doña Ana County

(575) 647-7350

[email protected]

845 N Motel Blvd, Las Cruces, NM 88007

Floodplain permits

Doña Ana County Office of the Flood Commission

Floodplain identification and administration, flood-hazard determinations and Unified Development Code compliance with the National Flood Insurance Program for Doña Ana County

(575) 525-5558

2480 Lakeside Dr., Suite C, Las Cruces, NM 88007

Septic permits

New Mexico Environment Department - Las Cruces Field Office

Onsite liquid-waste (septic) permit applications and review for the Las Cruces area, including Doña Ana County

575-288-2050

2301 Entrada del Sol, Las Cruces, NM 88001

Online permits →

Contact details are copied from each office’s official page and were checked against it on September 24, 2026.

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

Unincorporated Doña Ana County requires a building permit for residential construction, administered by the county's Building Services Division under the state-adopted residential and commercial building codes¹. Doña Ana County qualifies as an authority having jurisdiction under New Mexico rule, meaning it has a full-service building department with a certified building official and permitting, inspection and enforcement authority over general construction, electrical and mechanical-plumbing trades⁵. Statewide, no building or structure regulated by the code may be erected, enlarged, altered, repaired, moved, improved, removed, converted or demolished without a permit first obtained from the building official, though some small residential items are exempt, including one-story detached accessory buildings up to 120 square feet, fences up to 6 feet, and detached decks up to 200 square feet that meet the rule's conditions⁸. We could not confirm whether Doña Ana County offers a homeowner permit exemption from licensed-contractor rules; New Mexico's rule only allows a homeowner permit subject to specific limitations, so ask Building Services directly before you plan to be your own contractor⁴.

Who is the Doña Ana County building department, and how do you reach them?

Doña Ana County's Building Services Division coordinates the review and processing of permit applications and works closely with other county departments to confirm each application meets building codes, zoning regulations, and required setbacks⁹. The division accepts applications for commercial and residential building, plumbing, mechanical, electrical, and manufactured (mobile) home permits⁹. Reach Building Services at (575) 647-7350, by email at [email protected], or in person at 845 N Motel Blvd, Las Cruces, NM 88007⁹. Building codes statewide currently run on the 2021 International Residential Code, effective since December 14, 2023, and the 2021 International Building Code for commercial and multi-family work, effective since July 14, 2023¹⁰¹¹.

Does Doña Ana County have zoning?

Doña Ana County has zoning countywide under its Unified Development Code (UDC), which Community Development administers alongside the county's Comprehensive Plan, "Plan 2040," the county map atlas, GIS and rural addressing²¹². Community Development also supports the Planning & Zoning Commission and the Board of County Commissioners, the bodies that hear rezoning and land-use matters¹². New Mexico law lets a county zoning authority adopt an ordinance covering any county territory that isn't inside a municipality's own zoning jurisdiction, which is the basis for the county's authority over unincorporated land¹³. Reach Community Development at the same number as Building Services, (575) 647-7350, or at 845 N Motel Blvd, Las Cruces, NM 88007¹².

How do septic permits work in Doña Ana County?

Septic systems in Doña Ana County need a state permit, not a county one: the New Mexico Environment Department's Liquid Waste Program issues onsite wastewater permits statewide, and no one may install or modify an on-site liquid waste system without one, including payment of the permit fee, before construction begins³¹⁴. Doña Ana County residents apply through NMED's Las Cruces field office at 2301 Entrada del Sol; call 575-288-2050 to confirm current requirements¹⁵. About 34.5% of the county's soils are rated free of severe limits for a conventional septic drain field, better odds than many counties, but still worth a site evaluation before you commit to a design¹⁶. NMED generally acts within 10 working days after a completed conventional-system application, and if a public sewer becomes available and the local authority requires connection, the old system must be properly abandoned within 30 days¹⁴¹⁷. Off-grid sanitation has real limits here too: a privy may only handle human excreta and toilet paper, and other liquid waste must go to a permitted system, treatment unit, or public sewer, with a narrow exception for small amounts of graywater used for irrigation under strict setback and storage rules¹⁸.

Can you live in an RV or tiny home on your land in Doña Ana County?

New Mexico has an actual, detailed tiny-house rule, not just a general building code: a tiny house used as a single dwelling unit with full living, sleeping, eating, cooking and sanitation facilities can be up to 400 square feet excluding lofts, built to the state residential code and its tiny-house appendix, with a minimum ceiling height of 6 feet 8 inches in living space and 6 feet 4 inches in bathrooms and kitchens⁶. A tiny house still on a chassis with a permanent axle is treated as a recreational vehicle under state rules and must meet RV codes and licensing instead, until the axle comes off and it's set on a foundation⁶. A manufactured home needs its own installation permit before it goes on your land, valid for 180 days, and an unlicensed homeowner working on their own principal residence must either do the work personally or use division-approved licensees and sign the required acknowledgment¹⁹. Our research did not find a Doña Ana County ordinance directly addressing whether you can live in an RV on your own rural land outside a manufactured or tiny-house framework, so confirm with Community Development before you plan to live on-site that way¹².

Building a home in Doña Ana County: the steps, in order

Call Community Development at (575) 647-7350 to confirm your parcel's zoning under the Unified Development Code and any required setbacks before you design anything¹².
Ask the Office of the Flood Commission at (575) 525-5558 whether your parcel sits in an area with a 1% or greater annual chance of flooding²⁰.
If the site isn't on a public sewer, apply for a liquid-waste (septic) permit through NMED's Las Cruces field office at 575-288-2050, including proof of ownership, a site diagram and a floor plan¹⁵¹⁴.
Apply for your building permit through Doña Ana County Building Services at (575) 647-7350 or by email at [email protected]⁹¹.
Schedule required inspections as construction proceeds, including foundation, slab or under-floor, frame, weather-resistive barrier, and a final inspection; final electrical, plumbing and mechanical inspections must happen before the final general inspection²¹.
If your access road connects to a state highway, get a separate access permit from the New Mexico Department of Transportation before you build or modify it²².

What to check before you buy land in Doña Ana County

About 78% of Doña Ana County is federal land, and only a fraction is privately buildable, so confirm a parcel's ownership and access before you get attached to it²³. The county is dry and drought-prone, averaging just 9.9 inches of precipitation a year with severe drought in roughly a third of years, so water rights and well capacity deserve real scrutiny²⁴²⁵. About 88% of the land sits at a gentle 15% slope or less, which helps for building and access, but ask the Office of the Flood Commission whether the parcel is in a flood-hazard area before you buy²⁶²⁰. If you're buying a larger tract, New Mexico exempts the sale of a parcel of 35 acres or more from the state Subdivision Act when the land has been used primarily and continuously for agriculture for the preceding three years⁷. A driveway or access road onto a state highway needs its own access permit from NMDOT before you build or modify it²². The typical home value in the county runs about $289,376, with a median property tax bill near $1,404 a year at an effective rate around 0.7%²⁷²⁸²⁹.

Watch-outs

Doña Ana County's own confidence in its building-permit and zoning facts is medium, not high, because the sourced pages describe requirements and forms rather than a single definitive ordinance statement; confirm specifics with Building Services or Community Development before you rely on them¹².
We could not confirm a Doña Ana County ordinance addressing RV occupancy on rural land outside the state's tiny-house or manufactured-home frameworks; call Community Development before you plan to live in an RV while you build¹².

Sources

Written September 24, 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 Doña Ana County scores

Seclusion41100% ev.

Self-Sufficiency1196% ev.

Admin Boringness4390% ev.

Durability27100% ev.

Property Autonomy38100% ev.

Carry Cost85100% ev.

Evidence strength: 97%. This reports direct-source completeness and fallback use; it is separate from the score and is not a confidence interval. How it works →

$289kTypical home

0.7%Property tax

$2,316Land / acre

9.9"Annual rain

33.8% of yrsSevere drought

36.6 / yr (+26.8)Mid-century 100°F days

50.7 daysMid-century dry spell

0.89" (+5.1%)Mid-century 1-day rain

1.18×Wildfire change factor

100%Forward climate coverage

$1,212Home insurance / yr

1% / yrInsurance growth

0.59%Nonrenewal rate

county median (2+ published ZIPs)Insurance basis

1,369,016People within 2 hr

155,806Radius comparison (15 mi)

59.1People / sq mi

78%Federal land

88%Land at 15% slope or less

34.5%Septic soil without severe limits

775,520 acWorkable land screen

3.1%Wooded land

0.6 tonsBiomass / forest ac

61.9°FAvg temp

Answers from the rulebook for Doña Ana County

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

Doña Ana County rules

County-wide zoningPresent
The county's Unified Development Code establishes zoning districts (Transect zones) mapped across unincorporated Doña Ana County.
Doña Ana County Code Art. V: Zoning Districts and Requirements ↗Scouted from the county site, not yet independently re-checked

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
One more reviewed finding on this topic
- 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
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 NMAC identifies the New Mexico Environmental Improvement Board as the issuing agency and defines the department as the New Mexico Environment Department.
- More stringent city or county requirements may also apply.
maximum regulated flow: <= 5000 gallons per day (Systems requiring a discharge plan under 20.6.2 NMAC or an NPDES permit are outside this part.)
“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
Septic inspectionRequired
Liquid-waste systems subject to the New Mexico onsite wastewater permitting process.
- The system must not be covered before the inspection.
- Inspection must be requested from NMED 48 hours, or two business days, in advance.
- A Permit to Operate is issued after approved inspection.
inspection notice: 48 hours (NMED page also states two business days)
“Request Inspection by NMED 48 hours (2 business days) in advance (DO NOT COVER BEFORE INSPECTION)”
Apply for a Permit ↗Re-checked Sep 26, 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
Subdividing landRegulated (with conditions)
Division of land statewide in New Mexico into two or more parcels for sale, lease, other conveyance, or building development, subject to the New Mexico Subdivision Act and its statutory exceptions.
- The source defines subdivision as division of a surface area of land, including land within a previously approved subdivision, into two or more parcels for sale, lease or other conveyance or for building development, whether immediate or future.
- The Act contains exceptions, including certain agricultural conveyances, grazing or farming divisions, municipal-boundary divisions, family transfers, divisions creating no parcel smaller than 140 acres, and other listed exceptions.
“The board of county commissioners of each county shall regulate subdivisions within the county's boundaries.”
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 feesVariable (with conditions)
New Mexico Construction Industries Division permitting fees for covered construction work statewide.
- General building permitting fees vary by type of construction, square footage, type of materials, and construction costs.
- The official schedule separately publishes fixed fees for some electrical, LP gas, mechanical/plumbing, and other items.
- Applicants are directed to contact one of CID’s three offices for permitting fees.
“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)
Construction Industries Division permit applications in New Mexico.
- The official page states that permits can be completed through the online permitting portal.
- Specific application requirements may vary by permit type and local authority having jurisdiction.
“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.

Owner-builder exemption — Owner-builder exemptions for construction in unincorporated Doña Ana County.
Certificate of occupancy — Certificates of occupancy for buildings in unincorporated Doña Ana County.
Local zoning — Local zoning across Doña Ana County, including incorporated and unincorporated areas.
Zoning districts — Published zoning districts and maps for unincorporated Doña Ana County.
Minimum dwelling size — Minimum dwelling size in unincorporated Doña Ana County.

9 more unanswered

Minimum lot size
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 Doña Ana County

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

Over-appropriated / declining

The aquifer here is over-appropriated and declining. A domestic well is usually still permit-exempt, but long-term supply is a genuine risk.

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 ↗

Lower Rio Grande (Mesilla & Rincon Valleys)partial of county
Surface and most groundwater fully/over-appropriated Elephant Butte to the state line; basin-wide metering under a Lower Rio Grande Water Master District and active groundwater adjudication. New domestic wells still issued under 72-12-1.1 but metered; any new/larger right requires buying and transferring existing rights.
NM OSE Lower Rio Grande Basin ↗
Hueco Underground Water Basinlocalized 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. NM portion of the Hueco Bolson (shared with El Paso/Ciudad Juárez), mined for decades; new non-domestic supply is effectively unavailable and comes by transfer.
NM OSE Article 7 (Declared Underground Water Basins) ↗
Tularosa 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. Hydrologically closed basin; over 90% of stored groundwater is too saline to drink, so fresh-water appropriations are heavily constrained.
NM OSE Article 7 (Declared Underground Water Basins) ↗
Nutt-Hockett Underground Water Basinlocalized 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 under active administration (1997-98 hydrographic survey); new non-domestic appropriations need a permit.
NM OSE Article 7 (Declared Underground Water Basins) ↗
Mount Riley Underground Water Basinlocalized 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. Small SW-Doña Ana basin (Order 163, 2005); OSE holds jurisdiction, new non-domestic appropriations need a permit.
NM OSE Article 7 (Declared Underground Water Basins) ↗

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 Doña Ana County, New Mexico

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

Doña Ana County scores 25/100 on the Bolthole Index, a weak county profile. Its strengths: manageable long-term carry cost. Watch-outs: weak self-sufficiency basics: only 9.9″ of rain a year, in severe drought 33.8% of years and elevated mid-century heat, water, rain, or wildfire exposure.

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

Doña Ana County generally requires a residential building permit, and it enforces county zoning. Onsite septic is permitted by New Mexico Environment Department, Liquid Waste (Onsite Wastewater) Program. 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 Doña Ana County, New Mexico?

Land in Doña Ana County runs about $2,316 per acre, based on the latest county data.

What is the water situation in Doña Ana County?

Doña Ana County gets about 9.9" of rain a year, with severe drought in roughly 33.8% of years. On water rights, Doña Ana County lies in the Lower Rio Grande (Mesilla & Rincon Valleys) — Surface and most groundwater fully/over-appropriated Elephant Butte to the state line; basin-wide metering under a Lower Rio Grande Water Master District and active groundwater adjudication. New domestic wells still issued under 72-12-1.1 but metered; any new/larger right requires buying and transferring existing rights..

How remote is Doña Ana County?

A typical private-land location has about 155,806 people within 15 miles and 2,631,861 within 100 miles. These radius catchments are the published fallback where road routing is unavailable.

Building permits, zoning and septic rules in Doña Ana County, New Mexico

At a glance

Who to call

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

Who is the Doña Ana County building department, and how do you reach them?

Does Doña Ana County have zoning?

How do septic permits work in Doña Ana County?

Can you live in an RV or tiny home on your land in Doña Ana County?

Building a home in Doña Ana County: the steps, in order

What to check before you buy land in Doña Ana County

Watch-outs

Sources

Doña Ana County in New Mexico

How Doña Ana County scores

Find land. Bring the promising ones back.

Parcel due diligence

Answers from the rulebook for Doña Ana County

Doña Ana County rules

New Mexico rules that apply here

Still unanswered

Water rights & wells in Doña Ana County

Living off-grid in Doña Ana County, New Mexico

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

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

How much does land cost in Doña Ana County, New Mexico?

What is the water situation in Doña Ana County?

How remote is Doña Ana County?

How Doña Ana compares in New Mexico