If you own or manage honey bee colonies that at any time of the year are going to be settled in a WA State location, you will have to register with the WA State Department of Agriculture (WSDA).
The deadline for registering without having to pay late fees is April 1st of each year.
The WSDA collects all fees and the proceeds are used to fund honey bee research. The payment is not a tax. The WSDA only administers the collection and distribution of the funds.
You can find more information and the link to download the registration form for the current year in this link: https://agr.wa.gov/plantsinsects/apiary/default.aspx
You can download the WSDA 2014 report from this link: https://agr.wa.gov/FP/Pubs/docs/103-435HoneyBeeWkGroupReport121214.pdf