RCW 19.94.160: State standards.

Physical weights and measures standards that conform to the standards of the United States obtained by the state for use as state weights and measures standards are the primary standards for weight and measure, when certified as such by the national institute of standards and technology or any successor organization. The state weights and measures standards shall be kept in a place designated by the director and shall be maintained in such calibration as prescribed by the national institute of standards and technology or any successor organization.