Utah Code § 11-17-13
The state of Utah does hereby pledge to and agree with the holders of any bonds issued under this act and with those parties who may enter into contracts with any county or municipality under this act, that the state will not alter, impair or limit the rights thereby vested until the bonds, together with applicable interest, are fully met and discharged and such contracts are fully performed. Nothing contained in this act shall preclude such alteration, impairment or limitation if and when adequate provision shall be made by law for the protection of the holders of the bonds or persons entering into contracts with any county or municipality. Each county and municipality is authorized to include this pledge and undertaking for the state in such bonds or contracts.
Utah Code § 11-17-13