Tex. Water Code § 7.175

An emergency repair to an on-site sewage disposal system without a permit in accordance with the rules adopted under Section 366.012(a)(1)(C), Health and Safety Code, is not an offense under Section 7.172, 7.173, or 7.174 if a written statement describing the need for the repair is provided to the commission or its authorized agent not later than 72 hours after the repair is begun.