"Although Utah’s authorities are silent regarding many vacation policy issues, based on the contractual emphasis Utah has placed on vacation policies, an employer is likely free to implement the vacation policy of its choosing, including policies providing for the forfeiture of accrued vacation leave upon separation from employment. UT Admin. Code R610-3-4(B)(1). An employer is required to comply with the terms of the policy it chooses to implement. UT Admin. Code R610-3-4(B)(1)."

http://www.employmentlawhandbook.com/leave-laws/state-leave-laws/utah/