Sales tax is determined based on the state the order is being shipped to and the state’s sales tax rate. If you have locations in multiple states, we will need a valid tax-exempt certificate on file for each state to which we ship your purchases. Having a tax-exempt certificate on file with Rio Grande will lower or eliminate sales tax on your orders. Any product(s) that we ship to a state for which Rio Grande does not have a valid tax-exempt certificate on file for you will have sales tax collected.