For trekking, Nepal is the most popular country in the world Because of its snow Himalayan range. Every person has the curiosity to know how about drinking water in the trekking period. Tap water in trek also very well for drinking for Nepali people because it comes from Snow Mountain and glaciers.
But for tourists not sure they can direct drink or not because they have no habit. They can purify this water or use pills or chlorine drops and can drink. In some parts of trekking, you can buy mineral water but in some trekking routes,
you cannot buy mineral water because of plastic pollution control. In that part, you can find some safe drinking water stations from Annapurna Conservation Area Project. Or you can buy boiled filter water from the tea houses. In many of the Everest tea houses, you can find a mineral water bottle.
But it is quite expensive. Better you can bring water cleaning tablets by yourself. But never drink city water from the tap. it is very poor. you must buy mineral water for drinking in the city like Kathmandu and Pokhara.