Tex. Local Government Code § 9.004

(a) Except as provided by Section 9.0045, the governing body of a municipality on its own motion may submit a proposed charter amendment to the municipality's qualified voters for their approval at an election. The governing body shall submit a proposed charter amendment to the voters for their approval at an election if the submission is supported by a petition signed by a number of qualified voters of the municipality equal to at least five percent of the number of qualified voters of the municipality or 20,000, whichever number is the smaller.

(b) The ordinance ordering the election shall provide for the election to be held on the first authorized uniform election date prescribed by the Election Code or on the earlier of the date of the next municipal general election or presidential general election. The election date must allow sufficient time to comply with other requirements of law and must occur on or after the 30th day after the date the ordinance is adopted.

(c) Notice of the election shall be published in a newspaper of general circulation published in the municipality. The notice must:

(1) include a substantial copy of the proposed amendment;

(2) include an estimate of the anticipated fiscal impact to the municipality if the proposed amendment is approved at the election; and

(3) be published on the same day in each of two successive weeks, with the first publication occurring before the 14th day before the date of the election.

(d) An amendment may not contain more than one subject.

(e) The ballot shall be prepared so that a voter may approve or disapprove any one or more amendments without having to approve or disapprove all of the amendments.

(f) The requirement imposed by Subsection (c)(2) does not waive governmental immunity for any purpose and a person may not seek injunctive relief or any other judicial remedy to enforce the estimate of the anticipated fiscal impact on the municipality.