From 1 January 2020 a remote seller must register to report business and occupation (B&O) tax and collect retail sales tax when it has more than $100,000 in combined gross receipts sourced or attributed to Washington (as at 1 October 2026). SSB 5581 removed the 200-transaction test from 14 March 2019 and the earlier notice-and-reporting election from 1 July 2019.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.