Harvesting and Potable Use of Rooftop Rain Water to Tackle Imminent Drinking Water Crisis in Coastal Gujarat, India

Rooftop water harvesting is an ideal technique to collect and store rainwater for drinking purposes. However, with time, in spite of all precautions, there is a possibility of development of microbes in stored water, making it unsafe for drinking. An attempt was made at Navsari Agricultural University, Gujarat to design the rooftop water harvesting system in such a way that stored water meets the annual water demand maintaining the quality of water at minimum cost. The water harvesting system was constructed at six locations and water quality in the storage tanks was monitored at regular intervals. Physical, chemical and bacterial quality of harvested rainwater was evaluated in laboratory and the water was found to be of excellent quality. However, microbial growth was found to be present at few places over the time. Laboratory study was undertaken to find economical solution to remove microbes from the stored water before consumption using copper vessel, silver strip of 30 cm × 10 cm × 0.03 cm size, commercially available cloth filter, earthen pot, and control (without any treatment). The results revealed that copper vessel showed maximum inhibitory effect on coliform as well as total bacterial count when water was stored for 12 h and 24 h. Though, there was a slight increase in copper residue, but it remained within the permissible limits. Therefore, vessel made up of copper could safely be used for antimicrobial treatment to purify the drinking water. The methodology could be useful to meet the precariously deteriorating potable water situation in rural areas especially for the poor people of developing economies.