Wash. Rev. Code § 60.04.041
A contractor or subcontractor required to be registered under chapter 18.27 RCW or licensed under chapter 19.28 RCW, or otherwise required to be registered or licensed by law, shall be deemed the construction agent of the owner for the purposes of establishing the lien created by this chapter only if so registered or licensed. Persons dealing with contractors or subcontractors may rely, for the purposes of this section, upon a certificate of registration issued pursuant to chapter 18.27 RCW or license issued pursuant to chapter 19.28 RCW, or other certificate or license issued pursuant to law, covering the period when the labor, professional services, material, or equipment shall be furnished, and the lien rights shall not be lost by suspension or revocation of registration or license without their knowledge. No lien rights described in this chapter shall be lost or denied by virtue of the absence, suspension, or revocation of such registration or license with respect to any contractor or subcontractor not in immediate contractual privity with the lien claimant.
RCW 60.04.041