Summit County · 1,524 residents
Coalville ADU rules
Coalville: internal ADUs allowed with conditions; detached ADUs allowed only in limited cases.
Internal ADU (inside the home)
Detached ADU (backyard building)
Not yet fully verified · last reviewed September 7, 2026 See sources
Coalville ADU rules at a glance
| Rule | Internal ADU (basement, attic, inside the home) | Detached ADU (backyard building) |
|---|---|---|
| Allowed? | Allowed with conditions | Allowed only in limited cases |
| Minimum lot | Statewide statute includes a small-lot pathway around 6,000 sq ft for many internal ADUs — confirm how Coalville applies it on your zone. | No automatic statewide 11,000 sq ft detached mandate applies under the specified-municipality screen; local rules control. |
How our property map screens Coalville lots
The map colors parcels using the rules on this page and the recorded lot size. A color is a planning screen, not a permit; Coalville makes the decision.
- No numeric external minimum is recorded for Coalville. The map keeps the statewide 11,000 sq ft external screen and shows the researched status (limited) on the property report.
- Because external ADUs are limited in the Coalville research, the map does not mark a new external ADU as likely there.
- "Likely" above 15,000 sq ft is this site's planning band for a large recorded lot. It is not a sentence in the Coalville code. Owner occupancy, parking, setbacks, zones, and HOA rules below still have to be checked.
Planned communities, PRDs and PUDs
Reviewed on September 22, 2026 against this city's research file, its published ADU page where one was found, and Utah meeting packets. No adopted sentence was confirmed that allows or bans an ADU in every PUD, PRD, PRUD, or planned community. If the assessor class or subdivision name says PUD, PRD, PRUD, planned unit development, planned residential development, planned community, resort community, or master planned community, the map keeps that lot highly unlikely regardless of size. A plat, CC&Rs, or development agreement can still prohibit an ADU where the zone allows one.
Planning notes for Coalville
Coalville’s amendment record identifies §10-3-23 as the accessory-dwelling section and distinguishes ADU housing from short-term rental rules. Use the city’s current version when comparing an internal unit, an above-garage design or a separate building. A Coalville mailing address alone does not establish that city rules apply; confirm the parcel is inside city limits.
Bring these to your review
- City-boundary and parcel-zone confirmation
- Proposed floor area relative to the main dwelling
- Long-term occupancy plan and utility arrangement
The question to resolve first
Is this parcel under Coalville or Summit County jurisdiction, and which ADU review steps apply?
Sources
We link only to government sources and public meeting records. Codes change; confirm the current version with Coalville before you apply.
- Utah S.B. 284 (2026), enrolled bill
Statewide detached-ADU requirements for specified municipalities, operative October 1, 2026.
- Official Coalville website
Common Coalville ADU questions
Can you build an ADU in Coalville?
Coalville: internal ADUs allowed with conditions; detached ADUs allowed only in limited cases. This is planning guidance, not a permit. Confirm the zone on your parcel with Coalville.
What lot size does Coalville require for an ADU?
Internal ADU: Statewide statute includes a small-lot pathway around 6,000 sq ft for many internal ADUs — confirm how Coalville applies it on your zone. Detached ADU: No automatic statewide 11,000 sq ft detached mandate applies under the specified-municipality screen; local rules control.
What does it cost to build an ADU in Coalville?
Wasatch Front planning bands are often about $55,000–$145,000 for an internal suite, $70,000–$175,000 for a garage conversion, and $95,000–$250,000 or more for a new detached unit, before unusual site work. These are planning ranges, not bids.
Can an HOA block an ADU in Coalville?
City approval does not override CC&Rs or plat notes. Read the HOA documents and your subdivision plat before you design. A private restriction can stop a unit the city would otherwise allow.
Before you design: general checks for any Utah ADU
General planning advice, not Coalville code.
- Confirm the zoning district on the city zoning map. The county assessor’s “residential” class is not zoning.
- Read your HOA CC&Rs and subdivision plat notes; private restrictions can block a unit the city allows.
- Sketch existing and proposed parking. Driveway geometry and access often decide what fits.
- Ask early about sewer, water and electrical capacity; utilities can force a redesign.
- Expanding a building’s footprint usually triggers full setback and height rules.
Nearby city ADU rules
Want to know what fits on your Coalville lot?
Free, no obligation. We review your parcel against these rules and, if you want, introduce independent design and construction partners. Partners may pay us for referrals.
Utah ADU Builder provides educational planning guidance. This page is not legal advice and not a permit. Population: UGRC POPLASTESTIMATE / Census-derived municipal estimates (manual fill where UGRC blank). Editorial standards.