Wash. Rev. Code § 22.09.800
If any terminal warehouse at inspection points is provided with proper scales and weighing facilities, the department may weigh the commodity upon the scales so provided. The department at least once each year shall cause to be examined, tested, and corrected, all scales used in weighing commodities in any of the cities designated as inspection points in this chapter or such places as may be hereinafter designated, and after such scale is tested, if found to be correct and in good condition, to seal the weights with a seal provided for that purpose and issue to the owner or proprietor a certificate authorizing the use of such scales for weighing commodities for the ensuing year, unless sooner revoked by the department. If such scales be found to be inaccurate or unfit for use, the department shall notify the party operating or using them, and the party thus notified shall, at his or her own expense, thoroughly repair the same before attempting to use them and until thus repaired or modified to the satisfaction of the department the certificate of such party shall be suspended or revoked at the discretion of the department. The party receiving such certificate shall pay to the department a reasonable fee for such inspection and certificate to be fixed by the department. It shall be the duty of the department to see that the provisions of this section are strictly enforced.
RCW 22.09.800