Building rainwater catching roofs together in a salty area

In coastal Khulna many families go far for drinking water in the dry season. Plenty of rain falls in the monsoon, but there is no way to hold it. Those with tin roofs can fit clean gutters and collect rainwater in lidded containers. A few homes can take turns buying containers, keeping them clean and washing them once a year. Strain or boil the water before drinking. You need gutters under the roof, lidded containers and a few neighbours teaching each other.