Tex. Natural Resources Code § 131.303

If a person violates or threatens to violate a rule, order, or permit issued by the commission under this subchapter, the commission may request the attorney general to institute an action to obtain a permanent or temporary injunction, temporary restraining order, or other appropriate order enjoining the violation or threatened violation, or to recover a civil penalty of not more than $10,000 a day for each violation or threatened violation, or for both injunctive relief and civil penalty. The action shall be brought 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.