Utah Accessory dwellings (2021): what it allows on a lot
Accessory dwellings (2021) is Utah law, and the official source is at le.utah.gov.
Cities must allow an internal accessory dwelling unit in most homes on lots with a single family home.
Whether it applies to one lot turns on where the lot is and what it is zoned; the city, county or state office named in the law decides. Mapped areas are approximate. This is a plain reading of public law with its source, not legal advice.
Free, no account. ParcelSheet shows the lot's mapped size, parcel lines and flood zone, and this law on the lot's Utah sheet.
Other Utah laws on a lot: Geologic hazards.