In South Carolina, the state Agriculture Department inspected gas pumps and gave out a twenty page report. The reports are the records of the inspections from areas around the Midlands.
The report proves that some gas stations are fine, some give too much and some give too little.
Gas stations that give a lot could give as much as half a gallon per 20 gallons. As for the others, some give an ounce less per gallon.
As soon as the owners found out about the problems, they immediately went to fix it.
The report says that 31 out of 836 gas stations were giving to little, while 40 were giving too much.
Even though you can't inspect how much gas that you're getting at gas stations in other states, just be aware that some could be giving you a bit of free gas or less than you are paying for.