Utah Code § 10-2-502.5

(1) No sooner than three weeks after notice is provided under Subsection 10-2-501(3), the legislative body of the municipality in which the area proposed for disconnection is located shall hold a public hearing. (2) The municipal legislative body shall provide notice of the public hearing: (a) at least seven days before the hearing date, in writing to the petitioner and to the legislative body of the county in which the area proposed for disconnection is located; and (b) for the municipality, as a class B notice under Section 63G-30-102, for at least 10 days before the hearing date. (3) In the public hearing, any person may speak and submit documents regarding the disconnection proposal. (4) Within 45 calendar days of the hearing, the municipal legislative body shall: (a) determine whether to grant the request for disconnection; and (b) if the municipality determines to grant the request, adopt an ordinance approving disconnection of the area from the municipality. (5) (a) A petition against the municipality challenging the municipal legislative body's determination under Subsection (4) may be filed in district court by: (i) the petitioner; or (ii) the county in which the area proposed for disconnection is located. (b) Each petition under Subsection (5)(a) shall include a copy of the request for disconnection.