Answer:
the drinking water available is not always safe as supplied water is often polluted. One of the reasons for this is due to the fact that the surface and ground water in the Kathmandu Valley is deteriorating by natural and anthropogenic contamination's. The surface water is polluted by industry and domestic waste along with discharge of untreated sewage from tightly packed residential neighborhoods. It is without a doubt that the domestic sewage system is deemed one of the top sources of water pollution that seeps into rivers and lakes, which are the primary sources of drinking water.