(1) Except as provided in subsection (2) of this section, commodities in liquid form must be sold only by liquid measure or by weight, and, except as otherwise provided in this chapter, commodities not in liquid form shall be sold only by weight, by measure of length or area, or by count.
(2) Liquid commodities may be sold by weight and commodities not in liquid form may be sold by count only if such methods provide accurate information as to the quantity of commodity sold.
(3) The provisions of this section do not apply to:
(a) Commodities sold for immediate consumption on the premises where sold;
(b) Vegetables when sold by the head or bunch;
(c) Commodities in containers standardized by a law of this state or by federal law;
(d) Commodities in package form when there exists a general consumer usage to express the quantity in some other manner;
(e) Concrete aggregates, concrete mixtures, and loose solid materials such as earth, soil, gravel, crushed stone, and the like, when sold by cubic measure; or
(f) Unprocessed vegetable and animal fertilizer when sold by cubic measure.
(4) When adopting rules under RCW
19.94.190, the director may issue such rules as necessary to assure that amounts of commodity sold are in accordance with good commercial practice and provide accurate information to all interested parties.