Weighing and Measuring Devices

Stefan P. Parnay, Agriculture, Weights and Measures - Marin County

Measuring Devices

The Marin County Department of Agriculture, Weights and Measures is responsible for inspecting, testing, sealing and carrying out laws and regulations surrounding measuring devices used in commercial settings in Marin County. Instruments used to determine volume, distance, dimensions, and time are all types of measuring devices, but people are most often familiar with measuring devices like gas pumps and deli scales, but other devices include: 

  • A wide variety of scales including hanging, computing, platform, jeweler, cannabis and livestock
  • Taximeters
  • Timers in Car Washes, Laundromats, and Parking Garages
  • Wire and Rope Meters
  • Propane Meters
  • Wholesale Water Meters
  • Milk Tanks
  • Utility Meters for Electricity, Gas, and Water

Each meter and scale type requires its own special test equipment and have their own testing procedures which are outlined in the National Institute of Standards & Technology's Handbook 44. Each inspection tests the device's ability to accurately register within allowed tolerances, full and light loads, including confirming other legal requirements. The computation of bills/receipts using correct rate schedules is also verified during our tests. The standards we use are verified by the California Division of Measurement Standards on a routine basis for accuracy. 

As a member of the public it is important to keep in mind the rights you have as a consumer when conducting a transaction that involves a measuring device. To learn more or report possible violations of your consumer rights please visit our consumer protection page or contact our office at (415) 473-6700 to file a complaint. 

Image of scale with test weights

For Businesses

Businesses using measuring devices

If your business is looking to install and use a measuring device to sell a commodity please contact our office at (415) 473-6700 for further information.  If you are using a device for commercial purposes, it must be approved by the State and tested and sealed by our department. Many measuring devices that are used for commercial purposes must be installed by a Registered Service Agent (RSA). The installation of the meter directly affects performance. Wiring and meter connections are vital to correct metering of electricity, while plumbing and level installations of gas vapor and water meters are critical to their accuracy. To locate a registered RSA near you that can serve your needs please refer to the CDFA Division of Measurement & Standards (DMS) Registered Service Agencies / Agent Listings.

Examples of devices include: scales; cordage, wire and fabric meters; taxi meters; retail water meters; water, gas and electric sub-meters; propane meters, vehicle tank meters and gas pumps. You must register your device with us annually.

Businesses using a Point-of-Sale System (POS)

If you have a point-of-sale system, you must register with our department annually. Please visit our Price Accuracy program page for more information.

For non-commercial scales

Our department does offer testing for non-commercial scales. For more information please contact our office directly.

Standard used by RSA for calibration of large capacity scales

For Registered Service Agents (RSA)

If you are a RSA needing to provide a Place in Service Report please provide at the minimum the following information by fax to: (415) 473-7543

  • Name and address of service agency
  • Location of device(s). Name and address, including if available the unique identifier used by the business (e.g., pump or check stand number).
  • Name of service agent.
  • Date of adjustment, repair, placing, or replacing into service.
  • Name of device manufacturer(s). 
  • Model designation(s) and serial number(s) of the device(s).
  • On new installations, the National Institute of Standards and Technology or National Conference on Weights and Measures Certificate of Conformance number(s) for each separately approved component or device, if marked on the component or device.

For a template of a Place in Service report please use following resource:

For regulations regarding the above requirements or other possible requirements please read the following:

For Weighmasters

A person who, for hire or otherwise, weighs, measures, or counts any commodity and issues a statement or memorandum of the weight, measure, or count that is used as the basis for either the purchase or sale of that commodity or charge for service. California Business and Professions Code, Division 5, Chapter 7, requires all businesses operating as a Weighmaster to be licensed. For more information please contact our office or visit the CDFA DMS Weighmasters Enforcement Program webpage.