General Contact Number: (530) 621-5567


Image of Fuel for ThoughtGetting what you pay for at the gas station ...

As a motorist, you have to buy motor fuel (e.g., gasoline, diesel, propane) and other products at the gas station. At some point,you may wonder if you are. The NCWM has put together this brochure to assist you in becoming a more informed consumer at the gas station.



What you can do at the pump

Pricing / Computation 

Many factors draw motorists to a gas station, and price is near the top of the list. To be sure that you are being charged the correct amount based on the posted price, do the following: 

Keep in mind that the vehicle tank capacity stated in the owner’s manual is only an ESTIMATE. It may hold more or less than the stated capacity.

Check the prices posted on station signs that list the grade of gasoline and type of service you select (full, self, cash/credit). Make sure the price is the same as the price per gallon on the dispenser face for the grade, type of fuel, type of service, and method of payment you select. Carefully note any qualifications or conditions required to obtain the discount for the cash/credit price.

Make sure that the numbers on the face of the dispenser for SALE and GALLONS are set to ZERO before you begin pumping gas. If the previous sale still appears on the dispenser when you start pumping gas, you can become the victim of an inflated purchase.

Multiply the indicated gallons delivered by the price per gallon to assure that the dispenser is correctly computing the price. (If you do not have time to do this at the station, get a receipt or write the numbers down and do the math at home.)

If you make a credit card purchase, check to be sure you have been charged the correct amount and take your receipt with you.

At full-service stations, observe attendants as they fill your tank or add liquids such as oil, transmission fluid, engine coolant to be sure they add the entire product. Ask the price of these products before the attendant opens the containers.

Answers to some frequently asked questions ...


Octane number is a measure of gasoline’s antiknock performance – its ability to resist knocking (a metallic pinging sound) as it burns in a vehicle’s engine. When you compare gasoline prices among stations, be careful to compare prices for the same octane. Using high octane gasoline in an engine that is designed for a lower octane is usually not recommended unless your engine knocks. Check your vehicle owner’s manual to see which octane the manufacturer recommends.


Oxygenated gasoline is conventional gasoline to which chemicals that are rich in oxygen have been added. This increases the octane and/or meets clean air regulations to help reduce carbon monoxide exhaust emissions. Oxygenated gasoline is required during winter months in those metropolitan areas that do not meet the Federal air quality standard for carbon monoxide. The most common oxygenates used are methyl tertiary-butyl ether (MTBE) and ethanol (alcohol). Oxygenated gasoline performs as well as conventional gasoline in most vehicles.

Reformulated gasoline (RFG) is gasoline blended to reduce potentially harmful emissions from vehicles. The Federal Government issues regulations that specify characteristics of the gasoline. Federal RFG is required in those metropolitan areas that do meet the Federal air quality standard for ozone. If you have questions about the use of oxygenated gasoline (and RFG), in your vehicle, consult the owner’s manual.

Important Note!

Service stations owners are required to keep their dispensers in good working order; however, equipment sometimes fails and mistakes do happen. If you have a problem involving incorrect pricing, short measure, or incorrect octane posting, call your local Weights and Measures Office. If the name of your local office does not appear in this brochure, look on the approval seal on the dispenser or in the telephone directory for the number.

This information is brought to you by: The National Conference on Weights and Measures (NCWM) and your local weights and measures officials. 

    Post Office Box 4025 
    Gaithersburg, MD 20885 
    Telephone: 301-975-4093 
    24-Hour-Fax Line 1-800-925-2453 

Helpful web site links:

National Institute of Standards and Technology (NIST): 

 National Conference on Weights and Measures (NCWM):

For more information contact your local Weights and Measures Office:

County of El Dorado Department of Agriculture
311 Fair Lane, Placerville, CA 95667
(530) 621-5520 ~ FAX (530) 626-4756

The National Conference on Weights and Measures is sponsored by: National Institute of Standards and Technology (NIST).