Davis County

Current Fruit Heights regulation only permits internal and attached ADU's. 

https://www.fruitheights.gov/DocumentCenter/View/2625/accessorydwelling2022

Bountiful City allows ADUs, both internal and external units subject to meeting code requirements. 

https://www.bountifulutah.gov/Bountiful-City-Planning---ADU-Information

Centerville allows Internal ADU's within an existing, owner‑occupied single‑family home (you HAVE to live on the same property). The Zoning Administrator reviews and approves ADU applications administratively. You must meet size, owner‑occupancy, parking, safety, and design requirements set out in City code. ADUs are intended for long‑term occupancy (30+ days), and short-term rentals are not permitted. 

https://s3-us-west-2.amazonaws.com/municipalcodeonline.com-new/centerville/zoning/documents/1633730892_Ord.%20No.%202021-18%20Internal%20ADUs.pdf

In Farmington, ADU's and internal ADU's are allowed under specific zoning codes. Regulations limit properties to one ADU per single-family home, require connection to a permanent concrete foundation, mandate extra off-street parking, and enforce size limits where the ADU is subordinate to the main dwelling. 

https://farmington.utah.gov/wp-content/uploads/2025/05/250116_Farmington_ADU_Toolkit-1-1.pdf

https://farmington.utah.gov/wp-content/uploads/2025/05/250116_Farmington_ADU_Checklist.pdf