What is the Municipal Bond Interest Addition
Interest from certain bonds, notes, and other evidences of
indebtedness (commonly known as municipal bonds) issued
by non-federal governmental entities outside Utah will be
subject to Utah's income tax if acquired on or after January 1, 2003.
However, interest earned on non-Utah municipal bonds is not subject to Utah tax if the issuing state (or political subdivision) does not impose an income tax on bonds issued by Utah, or the issuing state does not impose an income tax.
See details at Utah's website