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Kearns ADU rules

Kearns: internal ADUs allowed (lot 5,000+ sq ft); detached ADUs allowed (lot 5,000+ sq ft). Owner occupancy applies.

Internal ADU (inside the home)

Generally allowed

Detached ADU (backyard building)

Generally allowed

✓ Checked against city sources on September 24, 2026 See sources

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Kearns ADU rules at a glance

Kearns internal and detached accessory dwelling unit rules
RuleInternal ADU (basement, attic, inside the home)Detached ADU (backyard building)
Allowed?AllowedAllowed
Minimum lot5,000 sq ft. Kearns' ADU rules allow internal and attached ADUs on single-family lots of 5,000 sq ft or more, but the zoning use table lists them only in the R-1-6 and larger zones, so confirm eligibility for R-1-5 lots with planning staff.5,000 sq ft. Kearns allows detached ADUs on single-family lots of 5,000 sq ft or more, well below the 11,000 sq ft statewide floor that starts Oct 1, 2026.
Owner occupancyThe owner must live in the main home or the ADU (temporary absences of up to two years are allowed for medical, military or religious reasons with an on-site manager), may not collect rent on the unit they occupy, and must sign an affidavit that is recorded against the property.The owner must live in the main home or the ADU (temporary absences of up to two years are allowed for medical, military or religious reasons with an on-site manager), may not collect rent on the unit they occupy, and must sign an affidavit that is recorded against the property.
ParkingIn addition to the home's required parking, one on-site space is required for an internal or attached ADU; any garage spaces lost to the conversion must be replaced.In addition to the home's required parking, two on-site spaces are required for a detached ADU; any garage spaces lost to a conversion must be replaced.
Size limitsNot yet verified — confirm with the cityKearns' ADU section sets no separate floor-area cap; a detached ADU must fit within the zone's coverage limits (all buildings no more than 40% of the lot, and accessory structures no more than 25% of the rear yard).
HeightInternal and attached ADUs follow the zone's height limit for single-family homes.Detached ADUs are limited to 20 ft (28 ft for an ADU above a garage) and may not be taller than the existing home.
SetbacksInternal and attached ADUs follow the zone's setbacks for a single-family home; the ADU's separate entrance must be on the side or rear of the house, not the front or street-side yard.New detached ADUs need at least 5 ft side and rear setbacks (or the utility-easement width if larger) and 6 ft from the main home, cannot be in a front or corner side yard, and must sit at least 10 ft behind the front of the house; existing accessory buildings being converted keep the setbacks in effect when they were built.
ZonesPermitted in the R-1-6, R-1-7, R-1-8, R-1-10 and R-1-43 single-family zones; not allowed in townhomes, multifamily PUDs or other attached housing.Permitted in the R-1-5, R-1-6, R-1-7, R-1-8, R-1-10 and R-1-43 single-family zones.
Short-term rentalsKearns defines ADUs as units for long-term rental of 30 consecutive days or longer.Kearns defines ADUs as units for long-term rental of 30 consecutive days or longer.
Permit processRequires a building permit and a business license before the unit is rented, plus an owner-occupancy affidavit and a recorded Notice of Accessory Dwelling Unit; new owners must re-record and get reauthorization.Requires a building permit and a business license before the unit is rented, plus an owner-occupancy affidavit and a recorded Notice of Accessory Dwelling Unit; detached ADUs must be on a permanent concrete slab (or above a garage) and match the home's roof pitch and general color.

Proposed or pending changes

Not adopted as of September 24, 2026. They do not change the rules above until the city adopts them.

  • Apr 13, 2026: Kearns' attorney told the City Council that Kearns already allows detached ADUs and 'may make some tweaks' for S.B. 284 as part of annual land-use cleanup; no S.B. 284-specific ADU amendment was found in the codified history as of this review.

State law: detached ADUs from October 1, 2026

Kearns is a “specified municipality” under Utah S.B. 284. Beginning October 1, 2026, it must permit one detached ADU as a permitted use on a lot of 11,000 sq ft or more that has a detached single-family home. The city can still apply setbacks, height, design, owner-occupancy and limited parking rules, and it may allow detached ADUs on smaller lots. How the state ADU laws work.

How our property map screens Kearns 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; Kearns makes the decision.

  • The statewide map screen starts internal ADUs at 6,000 sq ft. Kearns's researched internal minimum is 5,000 sq ft, and the map uses that city number when the research names a status.
  • The statewide map screen starts a new external ADU at about 11,000 sq ft. Kearns's researched external minimum is 5,000 sq ft. Lots below that city minimum stay highly unlikely on the map even when they clear 11,000 sq ft.
  • "Likely" above 15,000 sq ft is this site's planning band for a large recorded lot. It is not a sentence in the Kearns 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.

Open Kearns on the property map

Sources

We link only to government sources and public meeting records. Codes change; confirm the current version with Kearns before you apply.

Common Kearns ADU questions

Can you build an ADU in Kearns?

Kearns: internal ADUs allowed (lot 5,000+ sq ft); detached ADUs allowed (lot 5,000+ sq ft). Owner occupancy applies. This is planning guidance, not a permit. Confirm the zone on your parcel with Kearns.

What lot size does Kearns require for an ADU?

Internal ADU: 5,000 sq ft minimum. Kearns' ADU rules allow internal and attached ADUs on single-family lots of 5,000 sq ft or more, but the zoning use table lists them only in the R-1-6 and larger zones, so confirm eligibility for R-1-5 lots with planning staff. Detached ADU: 5,000 sq ft minimum. Kearns allows detached ADUs on single-family lots of 5,000 sq ft or more, well below the 11,000 sq ft statewide floor that starts Oct 1, 2026.

Does Kearns require the owner to live on the property?

Internal ADU: The owner must live in the main home or the ADU (temporary absences of up to two years are allowed for medical, military or religious reasons with an on-site manager), may not collect rent on the unit they occupy, and must sign an affidavit that is recorded against the property. Detached ADU: The owner must live in the main home or the ADU (temporary absences of up to two years are allowed for medical, military or religious reasons with an on-site manager), may not collect rent on the unit they occupy, and must sign an affidavit that is recorded against the property.

How much parking does a Kearns ADU need?

Internal ADU: In addition to the home's required parking, one on-site space is required for an internal or attached ADU; any garage spaces lost to the conversion must be replaced. Detached ADU: In addition to the home's required parking, two on-site spaces are required for a detached ADU; any garage spaces lost to a conversion must be replaced.

Can an ADU in Kearns be a short-term rental?

Internal ADU: Kearns defines ADUs as units for long-term rental of 30 consecutive days or longer. Detached ADU: Kearns defines ADUs as units for long-term rental of 30 consecutive days or longer.

What does it cost to build an ADU in Kearns?

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 Kearns?

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 Kearns 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

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Utah ADU Builder provides educational planning guidance. This page is not legal advice and not a permit. Population: U.S. Census Bureau population estimate (2024). Editorial standards.