Accessory Dwelling Unit (ADU) Permit in Las Cruces, New Mexico
VerifiedConstruction of an accessory dwelling unit in Las Cruces is permitted through the standard residential building permit process (no separate ADU fee category is published by the City), subject to the statewide zoning floor established by New Mexico House Bill 425 (2023), codified as an amendment to NMSA 1978 § 3-21-1.
Verified 2026-07-02 · Source
When you need this permit
- Zoning authorities in New Mexico, including home-rule municipalities such as Las Cruces, must accommodate construction of one additional dwelling unit per lot within a single-family zoning district, regardless of lot size, per NMSA 1978 § 3-21-1 (as amended by 2023 House Bill 425)
- Statewide floor: the additional dwelling unit may not exceed 1,000 square feet
- Statewide floor: side and rear setbacks no more than 5 feet from the property line and 10 feet from any other structure on the property
- A zoning authority may not impose a single-family or owner-occupancy requirement specific to the additional dwelling unit as a condition of the permit
- Lack of adequate water, sewer, or other infrastructure capacity alone may not be used as a basis to delay or deny a building permit for the additional dwelling unit, per the statute
- The ADU structure itself is permitted as residential new construction — apply through the standard Residential Building Permit process (site plan, construction plans, ownership documentation) via the City of Las Cruces Citizen Portal (Accela)
- Trade permits (electrical, plumbing, mechanical) apply separately if the ADU includes those systems
Required documents
- Required
Building Permit Application
Submitted online through the City of Las Cruces Citizen Portal (Accela); ADUs are processed as residential new construction
- Required
Site Plan
Showing the ADU's location, setbacks from property lines and other structures on the lot
- Required
Construction Plans with Work Description
Full construction document set for the ADU structure
Fee schedule
| Fee type | Amount | Notes |
|---|---|---|
| Building Permit Fee (ADU processed as residential new construction) | $0.20 per square foot of gross floor area; minimum permit fee $50 | The City of Las Cruces 2023 Schedule of Fees does not publish a distinct ADU fee category — an ADU is billed under the same Residential Building Permit Fee section as new single-family construction, since it is a new dwelling structure on the lot. |
| Plan Check Fee | 25% of the building permit fee | City of Las Cruces 2023 Schedule of Fees |
Review timeline
3–3 business days
Las Cruces’s published plan-review target
Inspection process
- 1
Foundation
Before concrete pour
- 2
Frame
After framing and rough MEP complete
- 3
Final
All work complete per approved plans
Tips
- New Mexico HB425 (2023) sets a statewide floor requiring cities including Las Cruces to allow one additional dwelling unit per single-family lot, capped at 1,000 sq ft with 5-foot side/rear and 10-foot inter-structure setbacks — cities may not impose owner-occupancy requirements on the ADU.
- The City of Las Cruces does not publish a distinct ADU permit-fee line item — it is processed and billed as standard residential new construction at $0.20/sq ft.
- Confirm your specific zoning district's setback and lot-coverage rules with Las Cruces Community Development before designing, since the Las Cruces Land Development Code (Chapter 38, Zoning) may include additional district-specific standards beyond the statewide HB425 floor.
Frequently asked questions
- Can I build an accessory dwelling unit in Las Cruces?
- Yes. New Mexico state law (NMSA 1978 § 3-21-1, as amended by 2023 House Bill 425) requires zoning authorities, including home-rule municipalities like Las Cruces, to accommodate one additional dwelling unit per lot in single-family zoning districts, subject to a statewide 1,000 sq ft size cap and minimum setbacks. The ADU itself is permitted through the standard Residential Building Permit process.
- How much does an ADU permit cost in Las Cruces?
- Las Cruces does not publish a separate ADU fee category. An ADU is billed under the same Residential Building Permit Fee schedule as new construction: $0.20 per square foot of gross floor area, with a $50 minimum, plus a 25% plan check fee. Source: City of Las Cruces 2023 Schedule of Fees.
Sources & verification
Verified against official sources. Last reviewed 2026-07-02.
- City of Las Cruces Community Development Department — Building and Development Services (One Stop Shop) — official building department
- New Mexico House Bill 425 (2023 Regular Session) — Additional Dwelling Unit in Single-Family Zoning District (PDF, New Mexico Legislature)
- City of Las Cruces 2023 Schedule of Fees (effective February 1, 2023) (PDF)
- Apply for a Permit | City of Las Cruces
Fees, timelines, and adopted codes are researched from each jurisdiction's published records — see how we verify. Requirements change and vary by project, so always confirm the current details with the Las Cruces building department before you submit. PermitBase is an independent reference and is not affiliated with any government agency.
Other permits in Las Cruces
Accessory Dwelling Unit (ADU) Permit in other cities
Compare accessory dwelling unit (adu) permit fees across New Mexico →
Related guides
Project checklist — coming soon
Describe your project once and get every permit, document, and fee it triggers in Las Cruces — in one checklist. Leave your email and we'll tell you when it's ready.
We only use your email to send permit updates. No spam, unsubscribe anytime. Privacy.