Rio Rancho, NM Accessory Structures: ADU Rules (2026)

Rio Rancho's Zoning Code defines an Accessory Dwelling Unit in Section 154.03 as a separate, complete housekeeping unit, attached or detached, with its own entrance, kitchen, sleeping area and full bathroom, but not a mobile home. The dimensional rules are in Section 154.70(A): an ADU may not exceed 900 square feet or 50% of the primary structure, whichever is greater, and must be located on a lot 7,000 square feet or greater in area. Like other accessory buildings, an ADU cannot exceed the height of the primary structure or 24 feet, whichever is greater (Section 154.70(A)(1)). An additional off-street parking space is required, and it must not block a two-car garage. An ADU cannot be built without an existing primary dwelling on the lot (Section 154.70(A)(4)). The Code's land-use tables also limit second kitchens: a second kitchen may be in the primary residence or the ADU, but not both. Exterior materials must resemble the primary home once the structure exceeds 250 square feet, and match it above 600 square feet (Section 154.70(A)(2)). A building permit through the City's Development Services Department is required (Section 154.81). Rio Rancho administers its own zoning; the state does not preempt these accessory-unit standards.