Tex. Natural Resources Code § 85.351

(a) If it appears that a person is violating or threatening to violate the provisions of this chapter that were formerly a part of Chapter 76, General Laws, Acts of the 44th Legislature, Regular Session, 1935, as amended, or Title 102, Revised Civil Statutes of Texas, 1925, as amended, including provisions of this code formerly included in that title, or any rule or order of the commission adopted under those laws, the commission, through the attorney general, shall bring suit in the name of the state to restrain the violation or threatened violation.

(b) The suit shall be brought against the person violating or threatening to violate the law, rule, or order in a court of competent jurisdiction in Travis County, in the county in which the violation occurred, or in the county of residence of any defendant.