Is water harvested from rainwater hard or soft?
Water that contains dissolved minerals like magnesium and calcium is considered to be hard while water that contains only sodium ions is considered to be soft.
Since water harvested from rainfall does not contain any dissolved minerals, it can be considered as soft water.
However, if the rainwater comes in contact with different types of materials from which it may absorb different minerals before getting harvested, it may have to be considered as hard water. This harvested water might also need to undergo softening treatment before being used for any applications.