Tex. Water Code § 29.034

Members and employees of the railroad commission, on proper identification, may enter public or private property to inspect and investigate conditions relating to the hauling of oil and gas waste, to monitor compliance with a rule, permit, or other order of the railroad commission, or to examine and copy, during reasonable working hours, those records or memoranda of the business being investigated. Members or employees acting under the authority of this section who enter an establishment on public or private property shall observe the establishment's posted safety, internal security, and fire protection rules.