According to the Utah instructions:
A Resident is an individual that is
- domiciled in Utah for the entire year
- domiciled in Utah at any time during the year, OR
- maintained a place of abode in Utah and spent 183 days or more in the state during the year.
A Nonresident is an individual that was not domiciled in Utah at any time during the year. No place of abode was maintained in Utah during the tax year. The individual did not spend 183 days or more within the state.
A Part-Year Resident is an individual who meets the definition of a resident for only part of the year.
If a married filing joint federal return was filed and one spouse is a resident of Utah and the other is not, you may file your Utah return as married filing separate. To file separate returns within your account, you can file the federal return and wait for the return to be accepted. Then, change the filing status for the primary taxpayer and file a separate return for the first spouse. The second spouse will need to create a new account and file the separate state return in that account (if required to file).
For more information: