Research on water security in peri-urban regions of South Asian countries remains limited. We employed the Problem and Solution Tree tool to analyse the factors that impact water security in this region, specifically Nepal and Bangladesh. Water security in the peri-urban region in Nepal is related to the quantity of water, i.e., availability and distribution of water, and in Bangladesh to the quality of water. Climate change, lifestyle changes, population growth, urbanisation, and poor institutions and governance are the common causes of water insecurity in both countries. Conflicts, water-related health problems, and reduced agricultural productivity are the most common impacts in both study sites. Bangladesh predominantly relies on coping strategies, such as using potash alum and local water purification methods.

In contrast, Nepal relies on adaptation strategies such as tunnel farming, drip irrigation, water metering, rainwater harvesting, and recharge ponds. Bangladesh lacks community-based organisations, while Nepal has water user associations. Both countries face challenges in providing adequate water services. Multifarious interactions among biophysical, socioeconomic, and institutional and governance factors influence water security in the peri-urban areas. This study emphasises the significance of cooperation among diverse stakeholders in ensuring water security in peri-urban regions in South Asian countries.