(a) In this section, “retail public utility” has the meaning assigned by § 13.002.
(b) If a water supply, sewer, wastewater treatment, or solid waste disposal service operated by or for a municipality or county is being integrated into a regional water supply, sewer, wastewater treatment, or solid waste disposal service, the commission may enter into a compliance agreement with the regional service under which the commission will not initiate an enforcement action against the regional service for existing or anticipated violations resulting from the operation by the regional service of the service being integrated. A compliance agreement under this section must include provisions necessary to bring the service being integrated into compliance.

(c) If a water supply, sewer, or wastewater treatment service operated by a retail public utility, other than a municipality or county, is being integrated into a regional water supply, sewer, or wastewater treatment service administered by another entity, the commission may enter into a compliance agreement with the regional service under which the commission will not initiate an enforcement action against the regional service for existing or anticipated violations resulting from the operation by the regional service of the service being integrated. A compliance agreement under this section must include provisions necessary to bring the service being integrated into compliance.
(d) This section does not prohibit the commission from initiating an enforcement action against a regional service that is a party to a compliance agreement if the regional service does not substantially comply with the agreement.