Washington Revised Code Title 47. Public Highways and Transportation § 47.28.220. Compost products

(a) For the period July 1, 1996, through June 30, 1997, twenty-five percent of the total dollar amount purchased;

(b) For the period July 1, 1998, through June 30, 1999, fifty percent of the total dollar amount purchased. The percentages in this subsection apply to the materials' value and include services or other materials.

(3)(a) For purposes of this section, “compost products” means mulch, soil amendments, ground cover, or other landscaping material derived from the biological or mechanical conversion of biosolids or cellulose-containing waste materials.

(b) For purposes of this section, “biosolids” means municipal sewage sludge or septic tank septage sludge that meets the requirements of chapter 70A.226 RCW.