Are you getting cheated at the pump?

As customers, we're always trying to make sure we get the best deal at the gas pump. But how do you know you're getting what you pay for?

We went in search of answers by following one of the twenty gas pump inspectors in the state on a routine pump inspection.

"We try to go to every station once a year for our normal routine inspections. If we have a complaint from a consumer or if we have a concern from a fuel station, we'll actually send those inspectors that day or as soon as possible to take care of that concern," explained Derek Underwood, Assistant Commissioner with the South Carolina Department of Agriculture.

Underwood joined Lance Mudd, a state pump inspector, on a routine inspection of a Conway gas station. Mudd demonstrated how he uses two 5-gallon measuring devices to ensure that gas pumps are functioning correctly and accurately.

The first pump Mudd looked at was one a routine inspections. It turned out it was right on the money and perfectly calibrated, pouring the exact amount of gas being read on the meter.

But, that's not always the case.

In 2013, the state inspected and approved more than 73,000 pumps. More than 1,000 others were out of tolerance, pouring either more or less than what's being shown on the meter.

Surprisingly though, most of those out of tolerance were giving people more gas than they paid. The state found only 176 actually short-changing customers.

"Most of the time, the actual station is above tolerance. They're actually allowing more fuel to be pumped per what it states on the pump. So I don't know the exact percentage but more time than not the station itself is actually giving fuel away as opposed to taking fuel away from the consumer," Underwood explained.

What about the ones that are short-changing customers?

Underwood explained that it's rare the gas stations are doing it on purpose.

"These stations, if you have malicious intent or these stations are trying to short change the customers, they're not going to be in business long, so it's to their advantage too that they have an accurate and reliable legitimate business for these consumers. Because they want us to come here as much as the public does to make sure that the pumps are calibrated as accurate as possible and they're not giving away fuel as well," Underwood said.

Mudd also pays close attention to the seals underneath the pump. If broken, that could indicate tampering.

"The repairmen that we license to do the calibration will seal it with one of their tags and you can tell whether or not that's been tampered with," Underwood said.

The department tries to test all the pumps in the state every year. You can see when the pump was last inspected just by looking at the sticker on every pump.

"We ensure that the buying public knows that when they go to a station and they see our stickers that they're getting a fair amount of gas for the purchase price that they pay," Underwood said.

Inspectors shut down pumps immediately until the problems are fixed. The state said most stations fix the problems before any fines are levied.