(a) In this section:
(1) “Municipal utility” means a retail public utility, as defined by § 13.002, Water Code, that is owned by a municipality.
(2) “Residential area” means an area used principally for private residences that is improved with at least 100 single-family homes and has an average density of one home per half acre.
(3) “Utility” includes a “public utility” and “water supply or sewer service corporation” as defined by § 13.002, Water Code.
(b) The governing body of a municipality by ordinance may adopt standards set by the commission under Subsection (c) requiring a utility to maintain a minimum sufficient water flow and pressure to fire hydrants in a residential area located in the municipality or the municipality’s extraterritorial jurisdiction.

(c) The commission by rule shall establish standards for adoption by a municipality under Subsection (b). The standards:
(1) in addition to a utility’s maximum daily demand, must provide, for purposes of emergency fire suppression, for:
(A) a minimum sufficient water flow of at least 250 gallons per minute for at least two hours; and
(B) a minimum sufficient water pressure of at least 20 pounds per square inch;
(2) must require a utility to maintain at least the minimum sufficient water flow and pressure described by Subdivision (1) in fire hydrants in a residential area located within the municipality or the municipality’s extraterritorial jurisdiction;
(3) must be based on the density of connections, service demands, and other relevant factors;
(4) notwithstanding Subdivisions (1) and (2), if the municipality owns a municipal utility, may not require another utility located in the municipality or the municipality’s extraterritorial jurisdiction to provide water flow and pressure in a fire hydrant greater than that provided by the municipal utility as determined by the commission; and
(5) if the municipality does not own a municipal utility, may not require a utility located in the municipality or the municipality’s extraterritorial jurisdiction to provide a minimum sufficient water flow and pressure greater than the standard established under Subdivision (1).
(d) An ordinance under Subsection (b) may not require a utility to build, retrofit, or improve infrastructure in existence at the time the ordinance is adopted.
(e) A municipality with a population of less than 1.9 million that adopts standards under Subsection (b) or that seeks to use a utility’s water for fire suppression shall enter into a written memorandum of understanding with the utility to provide for:
(1) the necessary testing of fire hydrants; and
(2) other relevant issues pertaining to the use of the water and maintenance of the fire hydrants to ensure compliance with this section.
(f) A municipality may notify the commission of a utility’s failure to comply with a standard adopted under Subsection (b).
(g) On receiving the notice described by Subsection (f), the commission shall require a utility in violation of a standard adopted under this section to comply within a reasonable time established by the commission. The commission may approve infrastructure improvements and make corresponding changes to the tariff or rate schedule of a utility that is a public utility as needed to permit compliance with this section.
(h) Notwithstanding any provision of Chapter 101, Civil Practice and Remedies Code, to the contrary, a utility is not liable for a hydrant’s or metal flush valve’s inability to provide adequate water supply in a fire emergency. This subsection does not waive a municipality’s immunity under Subchapter I, Chapter 271, Local Government Code, or any other law and does not create any liability on the part of a municipality under a joint enterprise theory of liability.