Few guest houses will provide laundry facilities on the trekking trail. In some areas, there are no laundry facilities available. The famous treks like Everest base camp have laundry facilities in most of the town. In those places where there are no laundry facilities, you can do it on your own. You can buy soap and the guest house will provide other required things. You can have a hanging place for wet clothes near the teahouse or in the teahouse.