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New Washington State Compost Rule

By Ashley Mihle, King County & Northwest Biosolids Outreach Committee Chair
Washington State recently enacted a bill, HB 2713, that requires local governments to consider and if feasible, use compost in their projects. The Washington State Code defines compost products as mulch, soil amendments, ground cover, or other landscaping material derived from the biological or mechanical conversion of biosolids or cellulose-containing waste materials (RCW 43.19A.010). It is important to note that this applies only to composted materials not to cake or pellets or in our case to blended products. 

Here’s what this means for your utility:

  • Review the law and consider if your government projects should use compost (Section 2) or if you meet the exceptions.
  • Consider requesting a legal determination from your Prosecuting Attorney or legal counsel to determine whether this law includes the use of compost derived from biosolids, or any additional questions that are specific to your agency. King County requested this determination for their agency, and found that since “RCW 43.19A.010 defines “Compost products" as mulch, soil amendments, ground cover, or other landscaping material derived from the biological or mechanical conversion of biosolids or cellulose-containing waste materials. Therefore the mulch, soil amendments, ground cover, or other landscaping material referenced in the bill can be those derived from biosolids.” As read, this would apply to composted products only,

An example request (make sure it has the links) is: 

“Under this recently signed law, local governments are required to consider and if feasible, use compost in their projects. Local governments are also encouraged to buy back compost from companies to whom they send organic waste.  It is not clear whether the state’s definition of “compost” includes biosolids-based compost. The law’s preamble mentions food waste compost, but an associated staff report for the legislation references a definition of compost that includes biosolids as a feedstock (see pg 2). Does the state’s definition of compost include biosolids compost, under this new law?”

  • If it’s feasible to use compost in your government projects and your legal determination is the same as King County’s, check if the specifications or policies used include biosolids compost (if not, try to get them included!).
  • This law includes a section that encourages purchasing agreements with an agencies’ compost processor(s) that buy back finished compost for use in government projects or on government land (Section 3). This section encourages (rather than mandates) and applies only to agencies providing residential composting service (e.g. curbside pick up) so does not apply to biosolids or wastewater which are collected via sewers and septage, not via residential composting.  
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