Cache County · 8,615 residents
Nibley ADU rules
Nibley: internal ADUs allowed; detached ADUs allowed (lot 10,000+ sq ft).
Internal ADU (inside the home)
Detached ADU (backyard building)
✓ Checked against city sources on September 24, 2026 See sources
Nibley ADU rules at a glance
| Rule | Internal ADU (basement, attic, inside the home) | Detached ADU (backyard building) |
|---|---|---|
| Allowed? | Allowed | Allowed |
| Minimum lot | Not yet verified — confirm with the city | 10,000 sq ft. Nibley lowered its detached-ADU minimum lot size from 12,000 to 10,000 sq ft on Aug 6, 2026 (the online code may still show 12,000 until it is updated); state law also guarantees a detached ADU on single-family lots of 11,000 sq ft or more starting Oct 1, 2026. |
| Parking | Nibley treats a home with an internal ADU as a two-family dwelling, which needs 4 off-street spaces in total. | Off-street parking is required under the city's parking rules, and the application must include a parking plan showing dedicated off-street spaces for both the ADU and the main home. |
| Size limits | Not yet verified — confirm with the city | Between 300 and 1,200 sq ft of living area (garage or shop space doesn't count). Only one ADU per single-family home, and none on lots with a two-family dwelling. |
| Height | Not yet verified — confirm with the city | Up to 30 ft, limited to two stories. |
| Setbacks | Not yet verified — confirm with the city | 30 ft front (35 ft on an arterial road), 10 ft interior side, 25 ft street side (35 ft on an arterial), and 10 ft rear (20 ft for a two-story ADU) in residential zones. |
| Zones | Nibley counts an internal ADU as two-family housing, which is permitted in the A, R-E, R-1, R-1A, R-2, R-2A and R-M zones. | Permitted in the A, R-E, R-1, R-1A, R-2, R-2A and R-M zones and in the C and C-N commercial zones; not allowed on registered wetlands or flood plains. |
| Permit process | Not yet verified — confirm with the city | Apply for an ADU Zoning Clearance ($100) with a floor plan, parking plan and proof of a fire extinguisher, then get a building permit and a certificate of occupancy. The ADU needs its own address and mailbox. Impact fees apply at multi-family rates, with water and sewer impact fees at half rate when the ADU shares the main home's meter. |
What the Nibley council decided
Recorded votes and actions on ADU rules, linked to the public meeting record on OpenUtah.
· City Council
Approved Ord. 26-09 amending ADU standards (lot size, impact fees, conversion of existing accessory buildings) as recommended by the Planning Commission (4-0).
Read the meeting record
Proposed or pending changes
Not adopted as of September 24, 2026. They do not change the rules above until the city adopts them.
- The online Nibley code (19.24.250) still shows the older text (12,000 sq ft lot minimum, 25% rear-yard cap, neighbor notice) and has not yet been updated with Ordinance 26-09 adopted Aug 6, 2026; the staff redline also proposed dropping the neighbor notice and rear-yard cap and adding a conversion process for existing accessory buildings. Confirm the final codified text when it posts.
State law: detached ADUs from October 1, 2026
Nibley 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 Nibley 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; Nibley makes the decision.
- The statewide map screen starts a new external ADU at about 11,000 sq ft. Nibley's researched external minimum is 10,000 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 Nibley 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.
Sources
We link only to government sources and public meeting records. Codes change; confirm the current version with Nibley before you apply.
- U.S. Census Bureau — Vintage 2024 population estimates, Utah incorporated places
July 1, 2024 population estimates for the city and Cache County (145,487).
- Utah Code 17-60-104 — Classification of counties
A county with 40,000 to 259,999 people is a county of the third class; Cache County (145,487) is third class.
- Utah Code 10-2-301 — Classification of municipalities
City class population thresholds.
- Utah S.B. 284 (2026) enrolled — Utah Code 10-21-304 detached ADUs
Specified municipalities must permit a detached ADU on lots of 11,000 sq ft or more with a single-family home, effective Oct 1, 2026; caps detached-ADU parking at 1 space (<650 sq ft) or 2 spaces (650+ sq ft).
- Nibley City — Forms (ADU Zoning Clearance application)
Accessory Dwelling Unit Zoning Clearance is needed before a building permit.
- Nibley City Consolidated Fee Schedule 2026-27 (public copy 8-6-2026)
ADU zoning clearance $100; ADU water, sewer, park and transportation impact fees.
- Nibley City Council agenda packet — Aug 6, 2026
Ordinance 26-09 staff report and redline of 19.24.250 (SB 284 compliance; Planning Commission recommended a 10,000 sq ft lot minimum).
- Nibley City Council official minutes — Aug 6, 2026
Ordinance 26-09 approved 4-0 as recommended by the Planning Commission; Resolution 26-09 fee schedule approved 4-0.
- Nibley City Council agenda — Aug 6, 2026 (Utah Public Notice)
Agenda items 15 and 16 on ADU standards and fees.
- Official Nibley website
Common Nibley ADU questions
Can you build an ADU in Nibley?
Nibley: internal ADUs allowed; detached ADUs allowed (lot 10,000+ sq ft). This is planning guidance, not a permit. Confirm the zone on your parcel with Nibley.
What lot size does Nibley require for an ADU?
Internal ADU: Not yet verified — confirm with the city. Detached ADU: 10,000 sq ft minimum. Nibley lowered its detached-ADU minimum lot size from 12,000 to 10,000 sq ft on Aug 6, 2026 (the online code may still show 12,000 until it is updated); state law also guarantees a detached ADU on single-family lots of 11,000 sq ft or more starting Oct 1, 2026.
How much parking does a Nibley ADU need?
Internal ADU: Nibley treats a home with an internal ADU as a two-family dwelling, which needs 4 off-street spaces in total. Detached ADU: Off-street parking is required under the city's parking rules, and the application must include a parking plan showing dedicated off-street spaces for both the ADU and the main home.
What does it cost to build an ADU in Nibley?
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 Nibley?
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 Nibley 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 Nibley lot?
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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.