Texas Health and Safety Code - HEALTH & SAFETY § 366.071. Occupational Licensing and Registration

(a) A person who constructs, installs, alters, extends, services, maintains, or repairs an on-site sewage disposal system or any part of an on-site sewage disposal system for compensation must hold a license or registration issued by the commission under Chapter 37, Water Code.

(b) A person designated by an authorized agent under Section 366.014 must hold a license issued by the commission under Chapter 37, Water Code.

(c) A person who conducts preconstruction site evaluations, including visiting a site and performing a soil analysis, a site survey, or other activities necessary to determine the suitability of a site for an on-site sewage disposal system must hold a license issued by the commission under Chapter 37, Water Code, unless the person is licensed by the Texas Board of Professional Engineers and Land Surveyors as an engineer.

(d) The commission may implement a program under Chapter 37, Water Code, to register persons who service or maintain on-site sewage disposal systems for compensation.