This Lehi ADU guide helps homeowners understand local ADU rules, likely cost ranges, permit considerations, and builder options before requesting quotes. Start with a free property check to see whether your Lehi property may be a fit for an internal ADU, basement ADU, garage conversion, attached ADU, or detached ADU.
ADU Rules in Lehi, Utah
Last verified: January 2026 · Always confirm with Lehi before design or construction.
| Internal / attached ADU | Permitted under current Lehi code (subject to zoning) — verify with Lehi |
|---|---|
| Detached ADU (today) | Permitted under current Lehi code (subject to zoning) — verify with Lehi |
| Garage conversion | Permitted under current Lehi code (subject to zoning) — verify with Lehi |
| Maximum ADU size | Up to 1,000 sq ft |
| Minimum lot size | 6,000 sq ft |
| Parking | One additional off-street space required |
| Owner occupancy | Required |
| Short-term rental use | Not allowed |
| Permit path | 6-10 week review · est. permit fee $3,000 - $6,000 · est. impact fee $2,500 - $5,000 |
| Utah state law | Internal ADUs in single-family zones are governed by Utah Code §10-21-303 (formerly §10-9a-530). |
| Official source | Lehi City Development Code |
2026 detached ADU law: Under Utah Code §10-21-304 (effective Oct. 1, 2026), qualifying municipalities must permit a detached ADU on a lot of at least 11,000 sq ft that has a single-family dwelling, subject to listed local restrictions. Whether your Lehi property qualifies depends on lot size, zone, and city implementation — verify with Lehi before relying on it.
Why Lehi Homeowners Choose Utah ADU Builders
Local Expertise
Builder partners understand Lehi's unique ADU zoning requirements including setback requirements, height restrictions, and design standards specific to Lehi. A streamlined permit process and strong local relationships with Lehi building departments ensure efficient project approvals.
Proven Track Record
Builder partners have completed multiple ADU projects in Lehi, including detached ADU construction and garage conversion builds. Construction timelines vary by project complexity and scope. Lehi clients may experience property value considerations.
Special Lehi Offer
Free ADU permit handling for Lehi residents
Free permit handling service when you start your Lehi ADU project this quarter. Includes zoning compliance and building department coordination.
ADU Services Available in Lehi
Choose the perfect ADU solution for your Lehi property. All services include full permit handling and compliance with Lehi zoning requirements.
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