Weights and measures are the state inspections that make sure a fuel pump delivers the exact gallons it charges for, so the customer gets what they pay for.
A state inspector tests each pump by drawing a known amount of fuel and checking that the meter reads true within a tight tolerance. The same office checks scales and other measuring devices in other trades, which is where the old name comes from. At a fuel site the focus is the pump meter.
The point is fairness on both sides. A pump that gives too little cheats the customer, and one that gives too much quietly cheats the operator. The inspection keeps the meter honest in either direction, and a passing pump usually gets a dated sticker showing it was checked.
For an operator, the stakes are practical. A pump that fails can be tagged out of service until it is repaired and retested, which means a dead island and lost sales. Keeping meters calibrated and ready is cheaper than getting caught short during a surprise visit.
In useThe inspector tests each pump against a calibrated measure, the meters read within tolerance, and the site keeps every island open with a fresh sticker.
See also Gross vs net gallons, Shrinkage, Automatic tank gauging (ATG)