The coastal environment of Bangladesh is characterized by excessive salinity in both ground and surface water resulting in poor coverage because of the paucity of drinking water. Ground water cannot be used as drinking water due to excessive salinity, iron and arsenic problem. Moreover, most of the water supply options are not feasible in this region. So, people are suffering intensely due to lack of safe water sources and diarrheal diseases break out several times in each year causing death to hundreds of people. Pond sand filter and the rainwater harvesting system are widely used alternative safe water source among other modern technologies in the coast. This book, therefore, provides the scientific evidence to proof, which technology have more potentiality to solve long term water crisis in water scarce area. It will also help to evaluate the functional ability of pond sand filter and rainwater harvesting system and limitation of these technologies. Therefore findings of this study will be very significant for further expansion, planning, implementing of such technologies in not only in salinity affected coastal regions but also in other arsenic prone areas in Bangladesh.