Washington resident here…no specific knowledge of tax laws so take this for what it is worth – a (somewhat) educated opinion. In just the past year Washington seems to have gotten more aggressive/crafty in pursuing tax revenue – this happened on both a purchase i made of a private vehicle and on where my vehicles are licensed. They come at you with a guilty until proven innocent POV. The logic appears to be driven by where the “use” of the asset is. I could see that being applied in the case of your laundry equipment purchase as well. LIke i said…don’t know anything for certain but wanted to share. Given that experience, I think your risk assessment is right and they will find a way to come for the sales tax $$. Good luck!