Ensuring domestic water sources for thousands of households in the Mekong Delta is one of the urgent needs. There are many people in coastal areas still have to directly use the canal water and underground water of poor quality for daily activities, especially during periods of drought, water shortage and salinity intrusion. There are a number of domestic water treatment technologies are products of scientific research that basically meet criteria such as investment cost, low operating costs, easy management, and simple maintenance. However, for those technologies to be put into practice, suitable for the living, economic and social conditions of the coastal provinces in Mekong delta and capable of being replicated, it is necessary to have specific mechanisms and policies. Based on a review of existing mechanisms and policies, this article has analyzed and proposed a number of policies to support the construction and installation of rain and surface water collection, storage and treatment equipment to proactively supply water for rural households and small residential clusters during periods of drought, water shortage, and salinity intrusion in the coastal provinces of the Mekong Delta.