Drinking Water Quality of Kathmandu Valley

A significant portion of drinking water sources in the Kathmandu Valley, including dug wells, deep borings, treated water, tap water, and other sources, exceeds World Health Organization (WHO) standards for key parameters. The study found that turbidity, iron, ammonia, and conductivity were common problematic factors across various water sources. Notably, 86% of groundwater samples (wells and borings) exceeded WHO standards for total Coliform bacteria, while 36% of treated water and 80% of tap water samples were contaminated with Coliform bacteria. Additionally, parameters such as pH, chloride, arsenic, and hardness frequently surpassed safe limits, particularly in untreated sources. The research analyzed 969 water samples collected from Kathmandu, Lalitpur, and Bhaktapur districts between March 2012 and March 2013, assessing physical, chemical, and microbiological parameters to assess compliance with WHO guidelines.

Koju, N. K., Prasai, T., Shrestha, S. M., & Raut, P. (2015). Drinking Water Quality of Kathmandu Valley. Nepal Journal of Science and Technology, 15(1), 115–120. https://doi.org/10.3126/njst.v15i1.12027