What is the compressed natural gas tax rate? The compressed natural gas tax rate is 21 cents per gallon. January 27, 2020 19:37 Related articles Is compressed natural gas subject to sales and use tax? What is the undyed diesel tax rate? Is there a minimum purchase requirement to qualify for the government exemption from petroleum taxes? I am a wholesaler with gasoline and/or undyed diesel fuel in stock that I previously purchased for sale. Do I need to pay a floorstock tax? Is methanol subject to gasoline or diesel taxes?