Here in WA if you are a resident and purchase out of state...you have 30 days to register the RV. You will be required to present proof of sales tax. If you don’t have proof you’ll be required to pay use tax. Use tax is calculated at the same rate as the sales tax at the purchaser’s address. The DOL agent at our location used NADA to find the RV value to tax. In addition to the general use tax rate, vehicles are charged an additional 0.3% motor vehicle sales/use tax. Also, according to the WA Driver Guide, "if you are a WA resident and purchase a vehicle in another state with the intention of driving it on WA roadway, you must register the vehicle immediately,"