ADU rules in Gallup

A detached backyard casita is allowed by right. Table 10-3-1 lists 'Dwelling Structure/Unit' under Accessory Uses with a 'P' (Permissive, meaning permitted by right) in ten of the eleven base districts: Rural Residential, Single-Family Residential, all three Multi-Family Residential districts, both Mixed-Use districts, General Commercial, Heavy Commercial and Industrial. The only blank cell, meaning prohibited, is the Mobile Home Park (MHP) district. Section 10-3-C-s(3) allows one accessory dwelling structure with kitchen and bathroom facilities per single-family residential dwelling unit, capped at 800 square feet, and 10-3-C-s(3)(c) bars RVs and mobile homes from being used as ADUs.

Gallup's ADU must be a separate building. The definition of 'Accessory, Dwelling Structure/Unit' (repeated at 'Dwelling, Accessory Structure') reads: 'A residential dwelling structure that is separate and subordinate from the primary single-family dwelling on the property. Accessory dwelling units must be built as a detached building.' The general accessory-structure rule reinforces it by requiring at least ten feet of separation from the principal structure (10-3-C-r(1)(f)). A basement conversion, an internal unit or an attached addition therefore cannot be permitted as an ADU. A second attached unit would have to qualify as a two-family dwelling (duplex), which Table 10-3-1 permits only in the three Multi-Family Residential districts and Mixed-Use Neighborhood; endnote 50 records that duplexes were deliberately deleted as permissive in Rural Residential and Single-Family Residential.

Section 10-3-C-s(3)(a) limits the accessory dwelling structure to one single-family dwelling unit occupying 'no more than eight hundred (800) square feet of living area', and 10-3-C-s(3)(b) requires it to meet all development standards applicable to the principal single-family dwelling, so the district setbacks and the 26-foot residential height cap apply. Placement rules are separate: it may not sit in the required front setback but may sit in a required side or rear setback if kept five feet off the lot line, and an accessory structure inside a required setback is capped at 16 feet in height (10-3-C-r(1)(e)). The Rural Residential, Single-Family Residential and Multi-Family Residential Low districts also cap a lot at one principal dwelling structure and three accessory structures total, and the ADU counts as one of the three.

Nothing in the Land Development Standards requires the owner to live on the property; the phrases 'owner occupancy', 'principal residence' and 'shall reside' appear nowhere in Title 10 as applied to ADUs. What the code does require is common ownership and no separate sale: 'Accessory structures shall be under the same ownership as the principal structure' and 'The accessory structures shall not be sold independently of the principal residential unit sale', immediately followed by 'Accessory dwelling structures may be rented' (10-3-C-r(1)(c)-(d)). The same subsection expressly lets an ADU have its own utility meter, an exception to the same-meter rule for other accessory structures. An occupancy condition does attach if the unit is used as a short-term rental, but that is an STR rule, not an ADU rule. New Mexico has no statewide ADU or owner-occupancy preemption.

Table 10-4-4 (Required Off-Street Parking Supply) lists 'Dwelling, Accessory Unit' under Accessory Uses at '1 space/accessory dwelling unit'. That is one space on top of the principal house's requirement, which is one space per dwelling unit up to two bedrooms and two spaces at three bedrooms or more. Section 10-4-A-a-ix makes Table 10-4-4 the default supply standard unless the Standards provide otherwise. Properties inside the Downtown Overlay district get relief: new construction may cut the required count by 30 percent where compliance is shown to be infeasible, and existing uses and structures owe no off-street parking at all.

The ADU is a by-right use reviewed over the counter. Table 10-3-1's legend defines 'P' as 'the use is permitted by right within the respective district', and the accessory Dwelling Structure/Unit row carries a P everywhere except the Mobile Home Park district. Table 10-5-1 classifies a Building Permit as an Administrative Approval that City Staff review and decide, with no notice, no public meeting and no Planning and Zoning Commission or Board of Adjustment step. Code section 9-1-6 conditions the building permit on meeting 'the zoning requirements of title 10 of this code' and, for a residential dwelling, on connection to city water and sewer. Note the split in permitting bodies: Gallup runs its own building department but does not issue mechanical, electrical or plumbing permits, which come from the New Mexico Construction Industries Division.

Long-term tenancy is settled: 10-3-C-r(1)(d) states in terms that 'Accessory dwelling structures may be rented', while barring sale of the ADU independently of the principal residence. Short-term renting is much tighter. Table 10-3-1 marks 'Short-Term Rental' as 'AC' (Accessory Conditional) in every residential and mixed-use district, meaning it is allowed only after the applicant obtains a Conditional Use Permit, a noticed public hearing item that expires in one year under Table 10-5-1. On top of that, 10-3-C-g-iii(4) provides that 'Guest stays may only occur within the dwelling unit that the owner or resident manager occupies', which on its face confines short-term guests to the owner-occupied unit and does not authorize renting out a whole detached ADU while the owner lives in the front house. Any short stay also triggers Gallup's 5 percent Lodgers' Tax, and 10-3-C-g-iii(1) makes the owner responsible for paying it.