Gas Leak Detectors - Question

If you use a liquid soap mixed with water a leak will show up even if it is very small.
If you do not want to go that way you can shut off all the valves at the appliances and clock the meter. There is a dial on the meter for this purpose. If you see movement on this dial after a minute, you have a leak in the line.
Those are the 2 ways that the utilities use for checking for leaks.