Texas Tax Code - TAX § 162.355. Fuel Presumed Subject to Tax

(a) All compressed natural gas and liquefied natural gas sold by a dealer and delivered into the fuel supply tank of a motor vehicle is presumed to be subject to tax, and the dealer is liable for the tax under Section 162.351(b) and in accordance with Section 162.012 unless the dealer maintains adequate records to establish that the fuel was exempt from tax under Section 162.356.

(b) All compressed natural gas and liquefied natural gas delivered into the fuel supply tank of a motor vehicle by a fleet user or other dealer not in connection with a sale is presumed to be subject to tax, and the fleet user or other dealer is liable for the tax under Section 162.352(b) and in accordance with Section 162.012 unless the fleet user or other dealer maintains adequate records to establish that the fuel was exempt from tax under Section 162.356.