Washington State Contractor verification:
Tools for Contractors. Use our Verify tool to see if a business you want to contract with has an active contractor registration; an active and paid-to-date workers’ comp account covering any employees. At the same time, you can check for safety violations, other information, lawsuits against their surety bond and more.
Verify a Contractor, Tradesperson or Business
http://www.lni.wa.gov/TradesLicensing/Contractors/HireCon/Verify/default.asp
http://www.lni.wa.gov/