Salt Lake County · 62,352 residents
Herriman ADU rules
Herriman: internal ADUs allowed; detached ADUs allowed (lot 10,000+ sq ft). Owner occupancy applies.
Internal ADU (inside the home)
Detached ADU (backyard building)
✓ Checked against city sources on September 24, 2026 See sources
Herriman ADU rules at a glance
| Rule | Internal ADU (basement, attic, inside the home) | Detached ADU (backyard building) |
|---|---|---|
| Allowed? | Allowed | Allowed |
| Minimum lot | Herriman's 2026 ADU ordinance sets no minimum lot size for an internal ADU beyond the zone's normal lot minimum, although the city's internal-ADU handout still lists 0.1377 acres (about 6,000 sq ft), so confirm with the city. | 10,000 sq ft. Detached ADUs are allowed on lots of 10,000 sq ft (0.2295 acres) or more, which is below the 11,000 sq ft statewide floor. |
| Owner occupancy | The owner (or an immediate family member) must live in either the main home or the ADU as a primary residence, and a notice of the owner-occupancy requirement is recorded on the property title. | The owner (or an immediate family member) must live in either the main home or the detached ADU, with a recorded owner-occupancy affidavit. |
| Parking | One additional off-street parking space is required; tandem parking is allowed. | One additional off-street space for a unit under 650 sq ft, or two for 650 sq ft or more (tandem allowed); garage spaces lost to a conversion must be replaced. |
| Size limits | An internal ADU can be no larger than 50% of the home's gross floor area or 1,000 sq ft, whichever is less. | Up to 1,000 sq ft of floor area (not counting covered or enclosed parking), and never larger than the main home. |
| Height | An internal ADU follows the normal height limit for the house in its zone. | Maximum 25 ft. |
| Setbacks | An internal ADU follows the normal setbacks for the house in its zone. | At least 10 ft from the rear lot line and 8 ft from side lot lines; not in the front yard or any recorded or utility easement; upper-floor windows facing a neighbor need a 6 ft sill height. |
| Zones | Allowed in all zones that allow single-family homes; only one ADU per lot, internal or detached, not both. | Allowed in residential and agricultural zones that permit single-family homes (the city lists R-1-10, R-1-15, R-1-21, R-1-43, R-2-10, R-2-15, A-1-10, A-1-21 and A-1-43); only one ADU per lot. |
| Short-term rentals | Short-term rentals are prohibited; rentals must be at least 30 consecutive days. | Short-term rentals are prohibited; rentals must be at least 30 consecutive days. |
| Permit process | A permitted use: an I-ADU application ($559 review fee) plus a building permit, and a business license if the unit is rented. | A permitted use with no conditional use permit: a D-ADU application ($559 review fee) plus a building permit, and a business license if rented; existing accessory buildings can be converted if they meet life-safety and nonconformity criteria. |
What the Herriman council decided
Recorded votes and actions on ADU rules, linked to the public meeting record on OpenUtah.
· City Council Regular Meeting · Approved (5-0)
City Council approved Ordinance 2026-11 permitting detached ADUs (10,000 sq ft minimum lot, one ADU per lot); vote taken from meeting transcript.
Read the meeting record· Planning Commission Meeting · Approved
Planning Commission approved its Feb. 4, 2026 minutes with a correction to the detached ADU recommendation motion (7,000 sq ft lot, 1,000 sq ft max).
Read the meeting record· City Council Regular Meeting · Continued
City Council continued (did not act on) the ordinance amending the Land Development Code regarding accessory dwelling units.
Read the meeting record· Planning Commission Meeting · Approved
Planning Commission recommended approval of detached ADUs with a 7,000 sq ft minimum lot, 1,000 sq ft max floor area and 25 ft max height.
Read the meeting record· Planning Commission Meeting · Continued
Planning Commission continued the detached ADU code amendment to its February 4, 2026 meeting.
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 council said it may consider lowering the 10,000 sq ft detached lot minimum later (Mayor Palmer, May 27, 2026), and the ordinance directs staff to track requests for ADUs on smaller lots and for both ADU types on one lot. Staff are also to bring back ADU impact-fee recommendations. No amendment adopted as of Sept 24, 2026.
State law: detached ADUs from October 1, 2026
Herriman 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 Herriman 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; Herriman makes the decision.
- The statewide map screen starts a new external ADU at about 11,000 sq ft. Herriman'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 Herriman 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 Herriman before you apply.
- Herriman City Council, May 27, 2026 — packet with Ordinance 2026-11 (Chapter 10-36 ADUs) (OpenCity)
Adopted ADU chapter text: lot size, size, height, setbacks, parking, owner occupancy, short-term rental ban, permitting; transcript records the 5-0 adoption.
- Herriman City Council, July 8, 2026 — packet with approved May 27 minutes (OpenCity)
Minutes confirm 'Councilmember Hodges moved to approve Ordinance No. 2026-11' and the 10,000 sq ft detached lot minimum.
- Herriman — Accessory Dwelling Units (Detached) page
City D-ADU page: 0.2295-acre lot minimum, one ADU per lot, $559 review fee, submittal list.
- Herriman D-ADU General Requirements (handout)
City handout restating the adopted detached ADU standards, zones, parking and fees.
- Herriman I-ADU General Requirements (handout, Aug 2026)
City internal-ADU handout; still cites former 10-29-26 and a 0.1377-acre lot minimum.
- 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 population thresholds.
- Utah Code 17-60-104 — Classification of counties
County class population thresholds.
- U.S. Census Bureau Vintage 2024 subcounty population estimates
July 1, 2024 population estimates for Utah places and counties.
- Official Herriman website
Common Herriman ADU questions
Can you build an ADU in Herriman?
Herriman: internal ADUs allowed; detached ADUs allowed (lot 10,000+ sq ft). Owner occupancy applies. This is planning guidance, not a permit. Confirm the zone on your parcel with Herriman.
What lot size does Herriman require for an ADU?
Internal ADU: Herriman's 2026 ADU ordinance sets no minimum lot size for an internal ADU beyond the zone's normal lot minimum, although the city's internal-ADU handout still lists 0.1377 acres (about 6,000 sq ft), so confirm with the city. Detached ADU: 10,000 sq ft minimum. Detached ADUs are allowed on lots of 10,000 sq ft (0.2295 acres) or more, which is below the 11,000 sq ft statewide floor.
Does Herriman require the owner to live on the property?
Internal ADU: The owner (or an immediate family member) must live in either the main home or the ADU as a primary residence, and a notice of the owner-occupancy requirement is recorded on the property title. Detached ADU: The owner (or an immediate family member) must live in either the main home or the detached ADU, with a recorded owner-occupancy affidavit.
How much parking does a Herriman ADU need?
Internal ADU: One additional off-street parking space is required; tandem parking is allowed. Detached ADU: One additional off-street space for a unit under 650 sq ft, or two for 650 sq ft or more (tandem allowed); garage spaces lost to a conversion must be replaced.
Can an ADU in Herriman be a short-term rental?
Internal ADU: Short-term rentals are prohibited; rentals must be at least 30 consecutive days. Detached ADU: Short-term rentals are prohibited; rentals must be at least 30 consecutive days.
What does it cost to build an ADU in Herriman?
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 Herriman?
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 Herriman 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 Herriman 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: U.S. Census Bureau population estimate (2024). Editorial standards.