The State tax is $.18 per gallon for gasoline, and either $.18 or $.26 per gallon for diesel, depending on whether a diesel vehicle is light class/exempt or use class. The tax rate is required to be posted on each pump using decals issued by the Arizona Department of Transportation. ADOT enforces fuel tax laws, and violations involving tax rate decals may be reported to ADOT online.

The service station must refund the $.08 per gallon if you request it. If a pump is used for sales to both classes of vehicles, a decal listing the $.26 per gallon tax rate must be posted on that pump. Violations involving the $.08 refunds may be reported to ADOT online.

If you are aware of attempts to evade fuel taxes, such as by using red-dyed diesel on Arizona highways, report the information to ADOT online, or call the ADOT fuel tax fraud hotline at 1-877- AZFuels (1-877-293-8357).

Note: The Arizona Department of Transportation is not responsible for regulating the proper measurement (fuel volume) of motor fuels (gasoline, diesel, propane, etc), or for analyzing fuel octane levels. If you feel that a fuel pump is not dispensing the indicated volume of fuel, or that fuel fails to meet octane standards, you should contact the Arizona Department of Weights and Measures.

Also note that the State of Arizona does not regulate the price of fuel.