ADU rules in West Bountiful

Detached ADUs are now allowed. Ord. 515-26 (adopted September 15, 2026) replaced Chapter 17.82 and repealed the old rule that barred any detached accessory structure from being used as a dwelling. A detached ADU is a permitted use in any zone that allows single-family homes as a permitted use, but §17.82.050.C sets a floor: "The minimum lot size required for a detached ADU in all single-family residential zones shall be eleven thousand (11,000) square feet." It may not sit in the front yard, must meet zone-specific setbacks (30 ft rear in A-1 and R-1-22, 20 ft rear in R-1-10, 10 ft side, 20 ft street side, 8 ft from the house), may not use a septic system, and an existing accessory building permitted on or before October 1, 2026 may be converted only if it was legally built and meets those setbacks.

Internal ADUs are a permitted use in any zone that allows single-family homes as a permitted use (§17.82.030), with no lot-size minimum. The code defines an internal ADU as one "created or existing within or physically incorporated into or structurally connected to a primary dwelling," meaning it "shares at least one common wall, floor, or ceiling"; a unit joined only by a breezeway, porch, deck, carport, or covered walkway counts as detached instead. A separate entrance may not face the front yard, and any addition must stay within the zone's lot coverage and setbacks (§17.82.040.F, .J). This matches Utah Code 10-21-303, which makes an internal ADU a permitted use in residential zones.

For detached ADUs, §17.82.050.D states: "The gross floor area of the ADU shall be no greater than fifty percent (50%) of the square footage footprint of the primary dwelling or one thousand (1,000) square feet, whichever is less. The minimum size of the ADU shall be 201 square feet." The whole detached structure counts toward that cap, including any garage, workshop, storage, or studio space in the same building. The internal ADU standards in §17.82.040 set no size limit, and Utah Code 10-21-303(1)(b) bars a city from limiting an internal ADU's size relative to the house.

For both types, the owner of record must live on the property as their principal residence, in either the primary dwelling or the ADU (§17.82.040.A; §17.82.050.A). Absences for business, medical, military service, or religious reasons are allowed for up to three continuous years, with a designated on-site manager. A recorded ADU agreement runs with the land: a new owner must file a new ADU application and occupy the property, or the ADU must be vacated immediately (§17.82.040.G; §17.82.050.K).

An internal ADU needs "a minimum of one (1) additional off-street parking space" (§17.82.040.C.1). A detached ADU needs one additional space if "smaller than 650 square feet" and two if "larger than 650 square feet" (§17.82.050.E.1, .2); the text does not address a unit of exactly 650 sq ft, and Utah Code 10-21-304(3)(b) caps the requirement at two for 650 sq ft or larger. Garage and driveway space counts, parking lost when an ADU is built in a garage or carport must be replaced, and outdoor stalls may be paved or gravel. The general parking table in §17.52.050 still lists one space per ADU; the more specific Chapter 17.82 rule applies to detached units.

§17.82.030 states that an ADU meeting the chapter's standards "is a permitted use in any zone that allows for single-family housing as a permitted use after approval of an accessory dwelling unit permit by the Land Use Administrator." The A-S, A-1, R-1-22, and R-1-10 zones each list ADUs "subject to Chapter 17.82" among their permitted uses. A building permit and a recorded ADU agreement are also required (§17.82.040.E, .G; §17.82.050.I, .K). No conditional use permit applies, consistent with Utah Code 10-21-304(3)(a).

By applying for an ADU, the owner agrees "that the main dwelling and the proposed ADU will not be used as a short-term rental, as defined by state code" (§17.82.040.K; §17.82.050.J). Utah Code 10-8-85.4(1)(e) defines a short-term rental as occupancy for fewer than 30 consecutive days, and the city's ADU page says an ADU may be leased for more than 30 days. "At no time shall both the ADU and the primary dwelling be rented as separate units," and any ADU lease must say it ends when the property is sold (§17.82.040.A, .I; §17.82.050.A, .M).