"Effective April 1, 2017, sales and use tax within the City of Seattle will increase one-half of one percent (.005). The tax will be used for transportation services." -- Washington DOR (This transit tax increase applies to cities in Snohomish, King, and Pierce counties).

To update the Sales Tax: Make the change before creating any invoices or sales receipts dated 4/1/17 or later.
In QuickBooks (Desktop version, aka QBDT), go to the Lists menu and select "Item List". Find your Seattle Sales Ta...