Cal. Bus. & Prof. Code § 12305

The department shall use the standards of the state to certify similar standards and any dissimilar standards that are dependent on the values represented by the state standards. Copies of the standards that have been compared and certified against the state standards shall become working standards that shall be used in the certification, calibration, and sealing of county field standards, and in the certification, calibration, and sealing of measurement devices submitted by state and local government agencies or by industry.