Wash. Rev. Code § 60.13.035
A person who controls or possesses amounts payable to the preparer of dairy products or the preparer's assigns, if the preparer or preparer's assigns is not a producer-handler, which are properly encumbered by a preparer's lien upon an account receivable shall not be obligated to pay a producer amounts to which the producer's preparer lien has attached until that person receives written notice of such lien, nor shall that person be liable to the producer for any amounts paid out prior to receipt of said notice. The notice required herein shall contain the information described in RCW 60.13.040(2). If requested by the person responsible for payment of such amounts, the producer must seasonably furnish reasonable proof that the preparer lien continues to exist and unless such proof is so furnished, that person has no obligation to pay the producer. A preparer of dairy products shall provide the name of the purchaser or marketing agent of the products to the producer upon request.
Failure to furnish the written notice as provided in this section shall not affect the status of the lien established under this chapter in regard to the relationship with other creditors.
RCW 60.13.035