Salt Lake County · 32,437 residents
Cottonwood Heights ADU rules
Cottonwood Heights: internal ADUs allowed (lot 6,001+ sq ft); detached ADUs allowed with conditions. Owner occupancy applies.
Internal ADU (inside the home)
Detached ADU (backyard building)
✓ Checked against city sources on September 24, 2026 See sources
Cottonwood Heights ADU rules at a glance
| Rule | Internal ADU (basement, attic, inside the home) | Detached ADU (backyard building) |
|---|---|---|
| Allowed? | Allowed | Allowed with conditions |
| Minimum lot | 6,001 sq ft. Internal ADUs are allowed only on lots larger than 6,000 sq ft (and not where the home is on a failing septic tank). | Cottonwood Heights sets no separate lot-size minimum for detached ADUs, but from Oct 1, 2026 state law requires the city to permit one on single-family lots of 11,000 sq ft or more. |
| Owner occupancy | The record owner must live in the main home or the ADU as their permanent residence (at least 200 days a year) and may not collect rent for the unit they live in; a notarized affidavit is required. | The record owner must live in the main home or the ADU as their permanent residence (at least 200 days a year) and may not collect rent for the unit they live in; a notarized affidavit is required. |
| Parking | One off-street space in addition to the home's required parking, with at least three off-street spaces total; the extra space cannot be tandem, and garage spaces lost to the ADU must be replaced. | Two off-street spaces in addition to the home's required parking; new parking may not be added in the front yard and tandem spaces are not allowed. |
| Size limits | Not yet verified — confirm with the city | A detached ADU must meet the zone's accessory-building limits for size, lot coverage and rear-yard coverage. |
| Height | Not yet verified — confirm with the city | Must meet the zone's accessory-building height limit. |
| Setbacks | Not yet verified — confirm with the city | Must be in the rear yard, at least 6 ft from the main home, and meet the zone's side and rear setbacks for a main house (flag lots use main-house flag-lot setbacks); fencing or landscaping buffers are required. |
| Zones | Permitted in the R-1, RR-1 and F-1 zones on lots over 6,000 sq ft; only one ADU per lot. | Conditional use in the R-1, RR-1 and F-1 zones; only one ADU per lot. |
| Short-term rentals | ADUs may not be used as short-term rentals (under 30 consecutive days). | ADUs may not be used as short-term rentals (under 30 consecutive days). |
| Permit process | Permitted use with an ADU application, affidavit, city inspection, building permit and business license ($100 license fee per the city checklist); the ADU license is renewed annually after an inspection. | Conditional use approved by the Planning Commission after a public hearing, plus ADU application, affidavit, inspection, building permit and business license (city checklist lists a $1,200 conditional use fee and $100 license fee); renewed annually after inspection. |
What the Cottonwood Heights council decided
Recorded votes and actions on ADU rules, linked to the public meeting record on OpenUtah.
· Planning Commission
Approved a conditional-use request (Project ADU-26-001) for an 800 sq ft detached ADU replacing a garage at 2982 E. 7375 S.
Read the meeting record· City Council
Approved Ordinance 465 amending 19.75.050 and 19.76.030 regarding separate utility meters for ADUs and guest houses (5-0).
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.
- Ordinance 465 (approved May 20, 2026) changed the rule on separate utility meters for ADUs; the online code for 19.75.050 still shows the older text ('The installation of separate utility meters for an ADU is prohibited'), so confirm the adopted wording with the city.
- S.B. 284 (effective Oct 1, 2026) bars requiring a conditional use permit for a detached ADU in a primarily residential zone on qualifying lots of 11,000 sq ft or more, and caps required parking at 1 space for detached ADUs under 650 sq ft (2 spaces at 650 sq ft or larger). Cottonwood Heights' code still lists detached ADUs as conditional uses with 2 extra spaces; no amending ordinance was found as of this review.
State law: detached ADUs from October 1, 2026
Cottonwood Heights 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 Cottonwood Heights 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; Cottonwood Heights makes the decision.
- The statewide map screen starts internal ADUs at 6,000 sq ft. Cottonwood Heights's researched internal minimum is 6,001 sq ft, and the map uses that city number when the research names a status.
- No numeric external minimum is recorded for Cottonwood Heights. The map keeps the statewide 11,000 sq ft external screen and shows the researched status (allowed with conditions) on the property report.
- "Likely" above 15,000 sq ft is this site's planning band for a large recorded lot. It is not a sentence in the Cottonwood Heights 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 Cottonwood Heights before you apply.
- Cottonwood Heights — ADU Licensing Requirements (How to add an ADU)
Official ADU page defining internal vs. detached ADUs and linking separate checklists.
- Cottonwood Heights Internal ADU Checklist
Permitted use on lots over 6,000 sq ft, owner occupancy, 1 extra parking space, no STR, $100 license, annual renewal.
- Cottonwood Heights Detached ADU Checklist
Conditional use with Planning Commission approval, 2 extra parking spaces, $1,200 CUP fee + $100 license, annual renewal.
- City Council, May 20, 2026 — Ordinance 465 on separate utility meters (OpenCity)
Council approved (5-0) amendments to 19.75.050 and 19.76.030 regarding separate utility meters.
- Planning Commission, May 6, 2026 — ZTA-26-001 separate meters for ADUs (OpenCity)
PC recommended allowing separate utility meters for ADUs/guest houses with an owner affidavit.
- Planning Commission, June 3, 2026 — detached ADU approval (OpenCity)
Example of the current conditional-use process for a detached ADU.
- Utah S.B. 284 (2026), enrolled copy
Enacts Utah Code 10-21-304 (effective Oct 1, 2026): specified municipalities must permit a detached ADU on single-family lots of 11,000 sq ft or more; defines 'specified municipality'.
- Utah Code 10-2-301 — Classification of municipalities
City class thresholds (third class = 30,000 to 64,999).
- Utah Code 17-60-104 — Classification of counties
County class thresholds (first class >= 1,150,000; third class 40,000 to 259,999).
- U.S. Census Bureau Vintage 2024 subcounty population estimates
July 1, 2024 population estimates for Utah places.
- Official Cottonwood Heights website
Common Cottonwood Heights ADU questions
Can you build an ADU in Cottonwood Heights?
Cottonwood Heights: internal ADUs allowed (lot 6,001+ sq ft); detached ADUs allowed with conditions. Owner occupancy applies. This is planning guidance, not a permit. Confirm the zone on your parcel with Cottonwood Heights.
What lot size does Cottonwood Heights require for an ADU?
Internal ADU: 6,001 sq ft minimum. Internal ADUs are allowed only on lots larger than 6,000 sq ft (and not where the home is on a failing septic tank). Detached ADU: Cottonwood Heights sets no separate lot-size minimum for detached ADUs, but from Oct 1, 2026 state law requires the city to permit one on single-family lots of 11,000 sq ft or more.
Does Cottonwood Heights require the owner to live on the property?
Internal ADU: The record owner must live in the main home or the ADU as their permanent residence (at least 200 days a year) and may not collect rent for the unit they live in; a notarized affidavit is required. Detached ADU: The record owner must live in the main home or the ADU as their permanent residence (at least 200 days a year) and may not collect rent for the unit they live in; a notarized affidavit is required.
How much parking does a Cottonwood Heights ADU need?
Internal ADU: One off-street space in addition to the home's required parking, with at least three off-street spaces total; the extra space cannot be tandem, and garage spaces lost to the ADU must be replaced. Detached ADU: Two off-street spaces in addition to the home's required parking; new parking may not be added in the front yard and tandem spaces are not allowed.
Can an ADU in Cottonwood Heights be a short-term rental?
Internal ADU: ADUs may not be used as short-term rentals (under 30 consecutive days). Detached ADU: ADUs may not be used as short-term rentals (under 30 consecutive days).
What does it cost to build an ADU in Cottonwood Heights?
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 Cottonwood Heights?
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 Cottonwood Heights 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 Cottonwood Heights 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.