Box Elder County · 2,224 residents
Willard ADU rules
Willard: 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
Willard 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 Willard 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 Willard 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; Willard makes the decision.
- No numeric external minimum is recorded for Willard. 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 Willard 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 Willard 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 Willard
Willard provides a dedicated ADU application through Planning and Zoning. The same page lists a separate conditional-use process for short-term rentals, so an ADU application should not be treated as permission for vacation-rental use. We can help establish the intended occupancy and the current requirements for your proposed layout.
Bring these to your review
- Preferred unit type and intended rental duration
- Site and floor plans
- Utility service and ownership details
The question to resolve first
What ADU approvals apply to this layout, and is any proposed rental use a separate approval?
Sources
We link only to government sources and public meeting records. Codes change; confirm the current version with Willard before you apply.
- Utah S.B. 284 (2026), enrolled bill
Statewide detached-ADU requirements for specified municipalities, operative October 1, 2026.
- Official Willard website
Common Willard ADU questions
Can you build an ADU in Willard?
Willard: 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 Willard.
What lot size does Willard require for an ADU?
Internal ADU: Statewide statute includes a small-lot pathway around 6,000 sq ft for many internal ADUs — confirm how Willard 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 Willard?
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 Willard?
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 Willard 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 Willard 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.