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...