Tex. Civ. Prac. & Rem. Code § 113.002

A local district or authority that enters into a written contract stating the essential terms under which the local district or authority is to provide water to a purchaser for use in connection with the generation of electricity waives sovereign immunity to suit for the purpose of adjudicating a claim that the local district or authority breached the contract by not providing water, or access to water, according to the contract's terms.