Texas Health and Safety Code - HEALTH & SAFETY § 366.051. Permits

(a) A person must hold a permit and an approved plan to construct, alter, repair, extend, or operate an on-site sewage disposal system.

(b) If the on-site sewage disposal system is located in the jurisdiction of an authorized agent, the permit is issued by the authorized agent; otherwise, the permit is issued by the commission.

(c) A person may not begin to construct, alter, repair, or extend an on-site sewage disposal system that is owned by another person unless the owner or owner's representative shows proof of a permit and approved plan from the commission or authorized agent.