Utah residents in the military do not lose their Utah residency or domicile solely by being absent due to military orders. They must file a Utah income tax return on all income, regardless of the source. If tax must be paid to another state on nonmilitary income, a credit may be allowed for the tax paid to the other state. If claiming this credit, complete and attach form TC-40S, Credit for Income Tax Paid to Another State.
Nonresidents stationed in Utah solely due to military orders are not subject to Utah tax on their military pay. However, nonresident military personnel residing in Utah and receiving income from Utah sources (other than active duty military pay) must file a Utah income tax return and pay any tax due on that other income. See instructions on page 16 and Pub 57, Military Personnel Instructions. You can access that article by clicking here
The nonresident spouse of a nonresident active military service member may be exempt from Utah tax on income received in Utah if certain conditions are met. If one spouse is a full-year Utah resident and the other spouse is a full-year nonresident, the couple may file separate Utah tax returns, even though they filed a joint federal tax return.
For full details on Military Personnel Filing in the state of Utah click here