Tex. Water Code § 13.0431

(a) In an appeal under Section 13.043(f) on the amount paid for water or sewer service under a written contract, the utility commission may not hold a hearing on or otherwise prescribe just and reasonable amounts to be charged under the contract unless the utility commission determines that the amount charged under the contract harms the public interest. A determination under this subsection becomes final for purposes of appeal in the manner provided by Section 2001.144, Government Code.

(b) A party adversely affected by a determination under Subsection (a) may seek judicial review of the determination. Judicial review of a determination under Subsection (a) shall be by trial de novo.

(c) The utility commission shall abate proceedings on the contract in the event of an appeal under Subsection (b) until the entry of a final judicial determination that a rate charged under the contract harms the public interest.

(d) Chapter 2001, Government Code, applies to an appeal under Subsection (b).

(e) The utility commission shall, before holding a hearing on or otherwise prescribing a just and reasonable rate to be charged under the contract, allow the contracting parties to amend the amount charged under the contract until at least 60 days after the date:

(1) of a final judicial determination in an appeal under Subsection (b) that a rate charged under the contract harms the public interest; or

(2) the determination made under Subsection (a) became final if a motion for rehearing was not filed on time.

(f) If the parties amend their contract under Subsection (e), a party may challenge before the utility commission the rate paid under the amended contract only:

(1) after the 5th anniversary of the date of the contract amendment; or

(2) during a period agreed to by the parties that begins after the 5th anniversary of the date of the contract amendment and ends on or before the 25th anniversary of that date.