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Smithfield City Zoning Code

17.92 ACCESSORY

DWELLING UNIT

17.92.010 PURPOSE OF CHAPTER

The purpose of permitting an accessory dwelling unit is to:

  1. Provide homeowners with a means of obtaining, through tenants in an accessory apartment, rental income, companionship, security and services, and thereby to enable them to stay more comfortably in homes and neighborhoods they might otherwise be forced to leave;
  2. Add inexpensive rental units to the housing stock to meet the needs of smaller households, both young and old;
  3. Make housing units available to moderate income households who might otherwise have difficulty finding homes within the city;
  4. Develop housing units in single-family neighborhoods that are appropriate for small households at a variety of stages in the life cycle, thereby lessening fluctuations in neighborhood demand for particular services.
  5. Allow more efficient use of existing single-family dwellings and public infrastructure.
HISTORY
Adopted by Ord. 15-20 on 11/11/2015
Amended by Ord. 22-11 on 8/24/2022

17.92.020 CONDITIONS

  1. A permit will be granted for a use to be known as an accessory dwelling unit, provided that the following standards and criteria are met:

    1. The original unit, including any accessory dwelling unit, shall all be considered a single-family residence rather than a “duplex” or “multi-family” as defined by the applicable building codes.
    2. A detached accessory dwelling unit shall not be connected to, and served by, the same water and sewer services that serve the primary building. See SMC 13.04.140 “Separate Connections” and 13.16.150 “Separate Building Connections Necessary”.
    3. Any new construction, remodeling or renovation of an existing structure to accommodate an accessory dwelling unit shall conform to the setbacks, height restrictions, health, fire, building and other code requirements current at the time of application. Additionally,
      1. An accessory dwelling unit must have its own entryway with eating, sleeping, and sanitation facilities that can be isolated from the original unit.
      2. Any wall of a detached accessory dwelling unit shall be a minimum of ten feet (10’) away from any wall of the primary structure.
    4. There shall be no more than one attached accessory dwelling unit and one detached accessory dwelling unit, for a maximum of two accessory dwelling units, per single-family residence.
    5. An accessory dwelling unit shall not exceed the lesser of seventy-five percent (75%) of the size of the original dwelling unit or fifteen hundred (1,500) livable square feet.
    6. The owner(s) of the residence shall occupy at least one (1) of the units on the lot; except for bona fide temporary absences of three (3) years or less for activities such as:
      1. A temporary job assignment, sabbatical, or voluntary service.
      2. The owner is placed in a hospital, nursing home, assisted living facility or other similar facility.
      3. City staff will require written documentation verifying the temporary absence.
      4. The owner(s) shall apply for a continuance of their accessory dwelling unit permit during their absence by notifying the Planning Department in writing. They shall include in the request their anticipated length of absence and estimated return date, a forwarding address, phone number and email address where they may be contacted by the city, and the names, phone numbers and email addresses of those who will act in their stead as the “surrogate” owners of the property in their absence.
    7. Parking:
      1. A single-family residence with one or more accessory dwelling units must have at least one (1) dedicated off street hard surfaced parking area, per accessory dwelling unit, available for use by the owner-occupant(s) and tenant(s). See Utah Code Annotated 10-9a-530 “Internal accessory dwelling units”.
    8. Other conditions for an accessory dwelling unit:
      1. An accessory dwelling unit shall not be sold separately or subdivided from the original single-family dwelling unit.
  2. Accessory dwelling units are allowed in "A" (agricultural zone), "RA" (residential agricultural zone) and "R-1" (single-family residential zone).
HISTORY
Adopted by Ord. 15-20 on 11/11/2015
Amended by Ord. 17-15 on 7/26/2017
Amended by Ord. 21-13 on 5/12/2021
Amended by Ord. 22-11 on 8/24/2022
Amended by Ord. 23-33 on 12/5/2023
Amended by Ord. 2025-11 on 5/14/2025

17.92.030 APPLICATION PROCEDURES

  1. Application for a permit for an accessory apartment shall be made to the zoning administrator in accordance with the conditional use permit procedures given in this title and, if required, shall include:
    1. . A new construction zoning clearance.
    2. A fee as set forth by the most recent prevailing fee schedule adopted by resolution of the city council to cover the costs of processing the application and code inspection.
  2. Within fourteen (14) days of the receipt of an application, the zoning administrator shall review and render a decision on the application. If the application fails to meet all of the conditions listed in SMC 17.92.020 of this chapter.
  3. The purchasers of a home that have a permit for an accessory apartment who want to continue renting their apartment must demonstrate that all conditions of the existing permit have been met.

HISTORY
Adopted by Ord. 15-20 on 11/11/2015
Amended by Ord. 17-15 on 7/26/2017
Amended by Ord. 21-13 on 5/12/2021
Amended by Ord. 22-18 on 9/14/2022

17.92.040 DEFINITIONS

  1. Definition of Accessory dwelling unit: A subordinate dwelling, which has its own eating, sleeping, and sanitation facilities which is:
    1. Within or attached to a single-family residential building, or
    2. Within a detached accessory structure on the same lot as the associated single-family residence.
  2. Accessory dwelling units may go by different names including accessory apartments, extended living areas, over-the-garage or basement living spaces, mother-in-law apartments, casitas, guest houses, tiny homes, etc.
  3. Accessory dwelling units are permanent structures. Mobile homes, travel trailers, boats, or similar recreational vehicles shall not be used as an accessory dwelling unit.
  4. Definition of Owner: An individual who is listed on a recorded deed as an owner of the property; any person who is related as a parent, parent in-law, child or stepchild to an individual who is listed on a recorded deed as an owner of the property; or an individual who is a trustor of a family trust who possesses legal ownership of the property.
HISTORY
Adopted by Ord. 22-11 on 8/24/2022
Amended by Ord. 24-20 on 9/11/2024

15-20

22-11

17-15

21-13

23-33

2025-11

22-18

24-20