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Weights and Measures FAQs


Q: How can I put 17 1/2 gallons of gas in my tank when it only holds 17 gallons?

A: Your auto manual never intended that your tank was 17 gallons and not a drop more. Depending on the size of the tank in your car, it may hold 1/2 to 2 gallons more than the stated capacity. Remember your gas gauge is only an estimate and your tank has not been calibrated. Gasoline pumps are tested and calibrated to the Cubic Inch (231 cubic inches = 1 gallon). We check over 20,000 gas pumps per year – it is rare to find one with a 1/2 gallon error.

Q: I find many pumps will jump up to 15 or 25 cents before any gas is pumped. This is a big ripoff!

A: When the dollar value on the pump is going up to 15 or 25 cents, there is a drizzle of gas coming that you cannot see because the nozzle is inserted in the tank opening. The pump will then click on and a large force will come out

Q: Do some station owners water down their gas to make it go further and to make more money?

A: The answer is NO. Gasoline and water do not mix. Water is heavier and will sink to the bottom; therefore, there is no advantage to add water to gasoline. Remember if you get water in your gas from a gas station and there is water detected at that station, they are obligated to pay for your damages. It is wise to keep your receipt to prove you purchased gasoline there.

Q: Am I responsible for the gasoline that is spilt on the driveway because the automatic shut-off valve on the nozzle did not shut off?

A; Yes. It is commonly understood that you assume the responsibility and liability for refueling your own vehicle. It is wise to remain close at hand if you are using the automatic shut-off valve to stop the pump just in case there is a malfunction.

Q: If a gasoline pump and a diesel pump are right together and I inadvertently put diesel fuel in my gasoline tank or vice-versa, am I responsible?

A: Yes. It is not wise for the station owner to put them together, but as long as they are labeled properly, you are responsible.

Q: What do I do if I suspect that there is water in the gas or the gas is bad?

A; Ask the station attendant or owner to test the tank for water by putting water-finding paste on the end of the dip stick, then lower the stick into the tank. If there is water in it, it will turn the paste a different color (usually purple) and there will be a definite line where the water is. Remember to test the water-finding paste by putting a little water on it before sticking it into the tank. If you have any problems, call Weights and Measures at 801-982-2261 immediately do not wait the longer you wait, the less we can do to help.

Q: As a tax payer, how do I know we got our money’s worth on the millions of dollars that was spent on the road reconstruction program of I-15?

A: Weights & Measures Inspectors do extensive tests on the large capacity truck scales that weigh each load of gravel used on the project. We also check the accuracy of the scales and water meters used to measure the ingredients for quality concrete on the project. Weights and Measures officials inspect scanners to make sure you are charged the correct price.


Weights and Measures officials inspect scanners to make sure you are charged the correct price.

What you can do:

  • Watch as the price of the item shows on the checkout register.
  • Ask the clerk to check the price if you think the scanned price is incorrect.
  • If the scanned price does not agree with the posted price, ask the store manager to correct it.
  • Save the cash register receipt in case you have questions or a problem later on.
  • If the problem is not resolved, contact your local weights and measures office at 801-982-2261 for help.


If you see that the scale at the check-out counter is not on zero, you can ask the clerk to put the scale on zero before they weigh any product or you will be paying for more than you get.

If you see that there is a difference in weight value between the hanging scale in the produce department and the check stand scale, remember the hanging scale is only for estimate and the check stand scale is the most accurate one.

What you can do:

  • Watch the scale and the amount registered. The scale should be placed so you can see the weight, price and other information displayed. If you have a question, ask to have the package weighed again before you buy.
  • Ask if the weight of the packaging has been deducted.
  • When you buy any product at the deli counter, you should pay only for the product, not for the weight of the container.
  • If you have any questions about how a store weighs or measures products, ask the manager for information first. He or she should answer your questions. If the problem is not resolved, contact your local Weights and Measures Office at 801-982-2261 for advice and assistance.


Posted on every gasoline pump that is in service are yellow stickers indicating the octane rating of the gasoline grade being pumped into the car. There is currently a great deal of concern as to which grade of gasoline rated at a certain octane is best for your car. Many people say the higher the octane rating the better it is for your car. Others say the cheapest is the best.

Many people coming from the lower altitudes of the United States are somewhat worried because the octane levels found in Utah are not as high as what they are accustomed to. This is not really a problem and the reason why will shortly be explained.

The number found posted on the gasoline pumps is a Relative Anti-Knock rating. This means that the gasoline will burn rather than detonate in the cylinders of your car. When a car engine begins to knock, supposing the engine is in good condition, it is because the fuel and air mixture is exploding before the pistons can reach the top of their stroke. This is extremely inefficient and can soon ruin an engine. Today’s cars are governed by a computer so the possibility of knocking has been greatly reduced but does sometimes occur. At lower altitudes, there is a need to have a higher Relative Anti-Knock rating due to the increased air pressure. Less pressure is required by the pistons in the engine to produce the most efficient power output. At the higher altitudes, a lower Relative Anti-Knock rating is necessary to achieve the same results. Due to the decrease of air pressure the engine’s pistons provide the necessary pressure to get an efficient burn and subsequent power output.

In almost all cases substances are added to the initial gasoline coming off the refinery’s column to get the Octane rating (Relative Anti-Knock rating) up to the necessary numbers in order for it to be sold. In the by-gone days, a lead derivative was the additive to get the octane number up. In fact, the highest rating that virgin gasoline can have is 100 Octane, but with additives, the Octane can go much higher. That is why high compression race car engines have to go to the airport. That is only place nowadays that you can get very high octane. Most of the octane boosting additives that you buy at the store have a high alcohol content so as to get the octane up. By adding the alcohol to the gasoline in the tank, it causes a more lean condition to occur and can damage the engine especially if someone decides that if a little is good, a lot is better.

Finally, the most asked question after the octane is: ‘Which gas is better for my car?” The answer is that if you are happy with the way your car runs on any brand of gas, keep getting that brand. Most of the gasoline that you buy is good quality, and if it isn’t, we at the Weights and Measures group want to hear about it so that we can do something about it.


  • Get a receipt which shows the seller’s name, address, phone number, the price, amount and kind of wood purchased. Write down the license number of the delivery vehicle.
  • A seller may not use terms such as “truckload”, “Face cord”, “Loose cord”, “rack” or “pile”.
  • A cord is 128 cubic feet To be sure you have a cord, stack the wood in a way that is easy to measure, then measure the firewood before using any.
  • If you feel you have a problem, contact the seller before you burn any wood. Take a picture of the stack if you think it is less than a cord.
  • If the problem cannot be resolved, contact your Weights and Measures office at 801-982-2261 before burning any wood.

Remember: A cord is 4′ x 4′ x 8′ or 2′ x 4′ x 16′


Liquid Propane Gas (LPG) vendors in the State of Utah are required to meet the tolerance and specifications outlined in the National Institute of Standards and Technology (NIST), Handbook 44.

A Weights and Measures LPG Inspector provides annual inspections to all Utah vendors dispensing LPG either through dispensers or trucks. These inspections include checking appropriate installation of the propane dispensers, checking calibration on meters and assuring appropriate safety requirements are in compliance.

Helpful Hints:

  • Always use a POL plug when transporting disconnected cylinders or tanks (full or empty).
  • Never allow your LP-gas tank or cylinder to be filled above the maximum safe level as indicated by the fixed liquid level gauge. Do not use the visible gauge for filling.
  • Federal DOT regulations require periodic inspections and requalifications of tanks. First inspection 12 years after manufacturing date and every five years after first inspection. This can be done at your local propane company.