Bangladesh is a tropical country and receives heavy rainfall during the rainy season. The average rainfall in the coastal region is more than 3000 mm, against an average rainfall of about 2400 mm in Bangladesh. In the coastal district, high salinity in surface and ground water and rainwater harvesting for drinking purposes is a common practice in a limited scale for a long time. In the present context of arsenic pollution of shallow ground water aquifer, rainwater harvesting is being seriously considered as an alternative option for water supply in the arsenic affected areas. There is...