City · Utah

ADU rules in Coalville

3 sources

These are the primary sources for accessory dwelling unit regulations in Coalville: the city's own zoning code, planning department pages, and permit guides. Start here before talking to anyone: the rules below are what your permit reviewer will apply.

Rules at a glance

Detached (backyard) ADU

Allowed

Detached ADUs (DADUs) are permitted uses in all zones except the Light Industrial zone; one DADU per primary single-family detached dwelling, and the lot must be at least 1/4 acre (10,890 sq ft). The Table of Uses lists 'Dwellings, accessory' as Allowed in AG, RA, R-1, R-2, R-4, R-8, CC, and HC and prohibited in LI.

§03-230.D; §08-020

Attached or internal ADU

Allowed

Internal ADUs (IADUs, a room, basement, or area above an attached garage within the primary single-family dwelling) are permitted uses in all zones except the Light Industrial zone; one IADU per primary single-family dwelling, lot must be at least 1/8 acre (5,445 sq ft), and the IADU may not change the home's single-family appearance.

§03-230.C

Maximum size

1,000 sq ft or 2/3 of the primary dwelling, whichever is less (detached); no size cap stated in the IADU standards

The DADU cap is measured exterior wall to exterior wall (§03-230.D.1). The IADU standards in §03-230.C list no size limit, though the Chapter 2 'Dwelling, Accessory' definition applies the same 1,000 sq ft or 2/3 cap to accessory dwellings generally.

§03-230.D.1; Ch. 2 Definitions, 'Dwelling, Accessory'

Owner occupancy

Depends

Owner occupancy is tied to rental, not creation: renting an IADU or a DADU is not allowed unless the primary dwelling is occupied as the owner's primary residence (§03-230.C.8 and §03-230.D.9). No owner-occupancy requirement is stated for an ADU housing the owner's relatives, domestic help, or house guests.

§03-230.C.8, §03-230.D.9

Extra parking

1 on-site space in addition to the primary dwelling's parking requirement (both IADU and DADU)

Required by §03-230.C.3 (IADU) and §03-230.D.4 (DADU). The base residential standard in the parking table is 2 spaces per single-family dwelling unit (§06-050).

§03-230.C.3, §03-230.D.4

Approval process

Permitted use

All ADUs, internal and detached, are administratively reviewed and approved by staff through the building permit and/or short-term rental process (§03-230.E). Exception: the Community Development Director may refer an application to a Planning Commission public hearing with a City Council decision, and the City Council must approve the business license for renting an ADU.

§03-230.E

Rental restrictions

Rental allowed with a City Council-approved business license and owner-occupied primary dwelling; DADU nightly rental prohibited; IADU nightly rental needs a Short-Term Rental Permit

Both ADU types may be rented long term, but the owner must obtain a business license (§03-230.C.5, §03-230.D.6, §03-230.E.2) and must occupy the primary dwelling as their primary residence (§03-230.C.8, §03-230.D.9). A DADU shall not be used as a short-term (nightly, under 30 days) rental (§03-230.B, §03-230.D.8); an IADU may be, with a Short-Term Rental Permit under §03-220 (§03-230.C.7, §03-230.E.3).

§03-230.B through E

The fine print: 8 caveats that can change the picture

Minimum lot size gates creation: an IADU requires a lot of at least 1/8 acre (5,445 sq ft) and a DADU requires at least 1/4 acre (10,890 sq ft) (§03-230.C.6, §03-230.D.7)
ADUs are not allowed in the Light Industrial (LI) zone; the §08-020 Table of Uses marks 'Dwellings, accessory' as prohibited there
No separate utility meter is allowed for either ADU type; the ADU must share the primary dwelling's meter (§03-230.C.1, §03-230.D.2)
Limit of one IADU and one DADU per primary single-family detached dwelling (§03-230.C, §03-230.D)
An ADU may not be a mobile home or be created within one (§03-230.C.4, §03-230.D.5; Ch. 2 definition excludes mobile homes)
Design controls: an IADU may not change the appearance of the home as a single-family dwelling, and a DADU must be consistent with the primary dwelling's appearance (§03-230.C.2, §03-230.D.3)
The Community Development Director can escalate any ADU application to a Planning Commission public hearing with final action by the City Council (§03-230.E.1)
Detached accessory buildings including ADUs 16 feet or less in height may not cover more than 50 percent of the rear yard area (zone chapters, e.g. §11-080 Requirements for Accessory Uses)

Summarized from Coalville's ordinance text, read July 2026; every row links the code section it came from. Rules often vary by zone and lot, so treat this as orientation, not a permit determination, and confirm with the planning department before you commit to a design.

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ADU regulations

Utah statewide law also applies

Utah sets baseline ADU rights at the state level. Where local rules are stricter than state law allows, state law usually wins, so both are worth reading.

See Utah statewide rules

Spotted something outdated?

Zoning codes change. If a link is dead or Coalville has updated its ordinance, report it and we'll verify against the official source.

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