California Code, Business and Professions Code - BPC § 12510

(1) Uses, for commercial purposes, or retains in his or her possession an incorrect weight or measure or weighing or measuring instrument.

(2) Sells any weight or measure used for commercial purposes, or weighing or measuring instrument which has not been sealed within one year, except weighing or measuring instruments required to be assembled prior to use.

(3) Uses any condemned weight or measure or weighing or measuring instrument contrary to law.

(4) Uses, for commercial purposes, or for determining the charge for a service, any weight or measure or weighing or measuring instrument which is not kept at a fixed location, which does not bear a current or previous year's seal, and which, upon test by the sealer, is found to be incorrect, unless a written request for an inspection of the weighing or measuring instrument has been made to the county sealer.  However, the use of any weight or measure or weighing or measuring instrument used by a public utility in connection with measuring gas, electricity, water, steam, or communication service subject to the jurisdiction of the Public Utilities Commission is exempt from this chapter.

(5) Sells or uses any device or instrument to be used or calculated to falsify any weight or measure.

(6) So locates or positions a weighing or measuring device used in retail trade, except as used exclusively in the preparation of packages put up in advance of sale, that its indications cannot be accurately read by the purchaser under ordinary circumstances.

(7) Uses, for commercial purposes, a weighing or measuring device designed to automatically compute price unless the computed price is a true mathematical computation of the amount times the price per unit.

(8) Willfully and knowingly uses, for commercial purposes, a measuring device designed to automatically compute price unless the indicators of quantity and the total computed price on the device has been returned to zero prior to the beginning of each delivery of that commodity or thing.

(9) Fails to deliver for test to a designated location after receipt of a written notice from a weights and measure official, any device that is ordinarily tested at a central location.

(10) Sells, rents, leases, loans, or knowingly installs an incorrect weighing or measuring instrument for commercial purposes.