30 Tex. Admin. Code § 344.38
Upon the licensed irrigator obtaining the seal, in accordance with this chapter, an impression of the seal shall be made on letterhead, or other business stationary, and maintained on file for review by the commission. Archival copies of all records given to the irrigation system's owner or owner's representative shall be maintained by the irrigator. Records will be maintained by the irrigator for a period of three years from the date installation, maintenance, alteration, repair or service was completed. Irrigators shall make all records of landscape irrigation services available within ten business days of any request made by authorized representatives of the commission or the local regulatory authority with jurisdiction over landscape irrigation.
30 Tex. Admin. Code § 344.38