Landscape Irrigation Licensing in the State of Texas

"A person may not sell, design, install, maintain, alter, repair, or service an irrigation
system—or consult in these activities—in this state unless the person is licensed by the TCEQ.
While connecting an irrigation system to a water supply, a licensed installer must be under
the direct supervision of a licensed irrigator."
http://www.tceq.state.tx.us/compliance/compliance_support/licensing/landscape_lic.html

Use this site to determine if the person that you are hiring to do the job is a Licensed Irrigator.

http://www5.tceq.state.tx.us/oce/olwe/