Tex. Water Code § 13.136

(a) Every utility shall file with each regulatory authority tariffs showing all rates that are subject to the original or appellate jurisdiction of the regulatory authority and that are in force at the time for any utility service, product, or commodity offered. Every utility shall file with and as a part of those tariffs all rules and regulations relating to or affecting the rates, utility service, product, or commodity furnished, including the utility's drought contingency plan required by the commission.

(a-1) Notwithstanding Subsection (a), a provision of a drought contingency plan does not constitute a rate as defined by Section 13.002.

(b) The utility commission by rule shall require each utility to annually file a service, financial, and normalized earnings report in a form and at times specified by utility commission rule. The report must include information sufficient to enable the utility commission to properly monitor utilities in this state. The utility commission shall make available to the public information in the report the utility does not file as confidential.

(b-1) The utility commission shall provide copies of a report described by Subsection (b) that include information filed as confidential to the Office of Public Utility Counsel on request, at no cost to the office.

(c) Every water supply or sewer service corporation shall file with the utility commission tariffs showing all rates that are subject to the appellate jurisdiction of the utility commission and that are in force at the time for any utility service, product, or commodity offered. Every water supply or sewer service corporation shall file with and as a part of those tariffs all rules and regulations relating to or affecting the rates, utility service, product, or commodity furnished. The filing required under this subsection shall be for informational purposes only.