California Code, Business and Professions Code - BPC § 12722

(a) In accordance with this chapter and regulations adopted by the secretary, any weighmaster may use a tare weight for a vehicle, container, or pallet that has been previously determined by a weighmaster. It is the responsibility of the party for whom the tare weight was established to maintain the tare weight within the variations prescribed by the secretary.

(b) Any weighmaster weighing any vehicle moving earth, stone, rock, sand, gravel, or asphalt paving material may use a predetermined tare weight. The issuance of predetermined tare weights are exempt from the provisions of Division 9 (commencing with Section 4000) of Title 4 of the California Code of Regulations. It is the responsibility of the party for whom the tare weight was established to maintain the actual weight so that the actual tare weight of the vehicle shall at no time exceed the recorded tare weight.