From Kansas Weights and Measures:
"The gas pump program tests more than 20,000 gas pumps each year to ensure that the consumer is getting all the fuel for which he or she has paid. This program has been very successful since changes were made to it in 1996. Prior to 1996, service companies were responsible for the annual gas pump tests. An increase in the petroleum inspection fee fund allowed the Weights and Measures program to assume responsibility for testing gas pumps. While the compliance rate for gas pumps in fiscal year 1997 was only 88 percent, it improved to 95 percent in fiscal year 2001 and has remained there or been higher. The program also checks Vehicle Tank Meters and Pipeline Meters.
Gas pump inspectors randomly take fuel samples to send to a private laboratory for analysis. It can be said, based on the results of these inspections, that fuel quality in Kansas is excellent. Ninety-seven percent to 99 percent of the fuel samples pass the quality testing performed by the laboratory every year. "