In the last 20 years, the widespread adoption of shallow tubewells in Nepal Terai region enabled substantial improvement in access to water, but recent national water quality testing showed that 3% of these sources contain arsenic above the Nepali interim guideline of 50 microg/L, and up to 60% contain unsafe microbial contamination. To combat this crisis, MIT, ENPHO and CAWST together researched, developed and implemented a household water treatment technology by applying an iterative, learning development framework. A pilot study comparing 3 technologies against technical, social, and economic criteria showed that the Kanchan Arsenic Filter (KAF) is the most promising technology for Nepal. A two-year technical and social evaluation of over 1000 KAFs deployed in rural villages of Nepal determined that the KAF typically removes 85-90% arsenic, 90-95% iron, 80-95% turbidity, and 85-99% total coliforms. Then 83% of the households continued to use the filter after 1 year, mainly motivated by the clean appearance, improved taste, and reduced odour of the filtered water, as compared to the original water source. Although over 5,000 filters have been implemented in Nepal by January 2007, further research rooted in sustainable development is necessary to understand the technology diffusion and scale-up process, in order to expand access to safe water in the country and beyond.

In the rural Terai region of Nepal, many tubewell drinking water sources are microbially and/or arsenic contaminated and consequently, millions lack access to “safe” water. Those who drink contaminated water may suffer from preventable water-borne diseases such as diarrhoea, stunting, skin lesions, and cancer. To combat this problem, a team comprising researchers from Massachusetts Institute of Technology (MIT), together with two local partners, Environment & Public Health Organization (ENPHO), and Rural Water Supply and Sanitation Support Programme (RWSSSP), have developed an award-winning household water filter, the Kanchan™ Arsenic Filter (KAF), for simultaneous arsenic and pathogen removal. The KAF is constructed using locally available labour and materials and is optimised based on the local socio-economic conditions. The first part of this paper explains the technology development process and the technical details of this innovation. The second part of this paper describes the dissemination activities since 2004. This dissemination model not only built capacity in local people towards long-term, user-participatory safe water provision, but also made a contribution to the local economy. As of January 2006, over 25,000 people have gained access to safe water as a result of the implementation of the KAF.

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This policy brief sets out key concepts, principles and practical implications for the citywide inclusive sanitation (CWIS) approach. Rapid urbanization, aging infrastructure, and climate change are exacerbating a sanitation crisis. The focus of most urban sanitation interventions remains incremental expansion of centralized sewer infrastructure; little attention is paid to reaching the poor, long-term service provision, financial viability, or the public system functions required to achieve those outcomes. Meeting SDG targets requires a radical rethink of the urban sanitation sub-sector. CWIS offers this. This paper presents a public services framework, set out by the Gates Foundation, for pursuing equitable, safe and sustained service outcomes, at city scale. It reviews the genesis and evolution of the CWIS framework and shares key principles and policy implications.

About 47% of Nepal's total population is living in Terai region and 90% of them are relying on groundwater as their major source of drinking water. About 200,000 shallow tubewells have been installed by different agencies in 20 Terai districts, serving 11 million people. Recently, arsenic contamination of groundwater has been recognized as a public health problem in Nepal. This has sensitized government, national and international nongovernment organizations working on water quality sector to carry out water quality assessment for arsenic in the affected communities. So far, 15,000 tubewells has been tested where 23% samples exceeded World Health Organization guideline value of 10 microg/L and 5% exceeded "Nepal Interim Arsenic Guideline" of 50 microg/L. It is estimated that around 0.5 million people in Terai are living at risk of arsenic poisoning (>50 microg/L). Some recent studies have reported the prevalence of dermatosis related to arsenicosis from 1.3 to 5.1% and the accumulation of arsenic in biological samples like hair and nail much higher than the acceptable level. Though some steps are being taken by government and private organizations to combat the problem, it has not been able to cover all the affected communities. Nepal still needs more research work on arsenic occurrence and effects and mitigation programs simultaneously.