Gas prices rose for the 34th consecutive day in a row Wednesday. The average price across California is now $4.18 a gallon.
With so much money being spent on gas, how can you be sure a gallon at the pump equates to a gallon in the tank?
The price for a gallon of gas can differ from station to station, but there is also tolerance in how accurately a gallon is measured.
When most people fill up, they're thinking of the final price, not final volume of fuel.
“You know, I never wondered about that before. I just always assumed that it was accurate,” said Laura Baldwin of Palo Cedro.
But when you get less gas than you paid for, it can be pretty frustrating.
“It actually took more gallons than my tank holds,” said Don Tretheway, who has experienced problems in the past.
Enter the local weights and measures department to ensure gas pumps are accurate.
“Every gas station in the county is tested once a year,” said Adam Davy, an Agriculture and Standards Investigator for the Shasta County Weights and Measures Department.
“Typically what we find is if a gas station is out of tolerance, it’s usually giving away more fuel,” said Davy.
Fuel is pumped till the display reads 5 gallons, then compared with the ‘provers’ on Davy's truck.
The volume must be accurate within less than half a tablespoon.
After the test is complete, the investigator places a seal on the pump so customers know they are getting what they paid for.
“Also the year that it was tested, also the initials of the inspector of investigator that tested that device,” said Davy.
For station owners, the seal tells customers they run an honest business, even when prices are on the rise.
“The gallons that they are supposed to get, we want them to get exactly what they pay for,” said John Gebauer, Owner of Palo Cedro Market and Shell Station.
During Wednesday’s test, the pumps came back accurate, and customers were happy.
“That reassures me even more,” said Laura Baldwin.
All of the fuel that is used during testing is poured back into the stations tanks so they do not lose any profit.