Weights and Measures Department

The Weights and Measures program protects consumers and prevents unfair business practices for a wide range of devices and business practices. Commercially used weighing and measuring devices are tested for their accuracy. Quantities of packaged products are routinely verified against their label statement. Fuels and other petroleum products are tested for quality and octane specifications. Sales of bulk commodities are monitored for proper documentation.

Device Registration & Inspection

Any device used to weigh or measure products or services for direct sale must be an approved type and annually registered with the Sealer of Weights and Measures. This includes gasoline pumps, gas and electric submeters, grocery and deli counter scales, taxi meters, water vending machines, truck scales, and yardage meters among others.

Registration fees help fund the inspection of commercial weighing and measuring devices throughout Merced County. Devices are affixed with the Division's seal upon demonstration of compliance with accuracy tolerances and device type standards. Devices that favor the device owner are immediately prohibited from being used. Device owners benefit when advised that a device favors the customer.

Quantity Control

Test purchases of packaged products are regularly conducted to verify, using statistical methods, the accuracy of the products' weight, count, or other measurement statements, and for proper labeling. Price verification is also performed on sale items, advertised prices, and register scanner accuracy.


Weighmasters are persons licensed by the Division of Measurement Standards, who certify the weighed, measured, or counted quantity of any commodity. Specific criteria must be followed when issuing weighmaster certificates. Weighmasters are regularly inspected to ensure the accuracy of their certifications.

Service Agent

Persons that sell, rent, install, service, or repair commercial weighing and measuring devices are required to be licensed with the Division of Measurement Standards. Device repairmen are required to notify the Sealer of the installation or repair of any commercial weighing and measuring device. County Weights and Measures inspectors may validate the accuracy of their repairs.

Petroleum Products

Samples of gasoline and other petroleum products are tested for compliance with quality and octane standards.