Potential for potable water savings by using rainwater: An analysis over 62 cities in southern Brazil

Water availability has been a matter of concern all over the world. This paper describes the water availability scenario in the state of Santa Catarina, southern Brazil, and evaluates the potential for potable water savings estimated for the residential sector of 62 cities in the state. Water availability in Santa Catarina amounts to about 10,000m3 per capita per year, but it is predicted to be lower than 2000m3 per capita per year from 2100 onwards. As for the potential for potable water savings by using rainwater, it is shown that it ranges from 34% to 92% depending on the potable water demand verified in the 62 cities, with an average potential for potable water savings of 69%. Results demonstrate that if there were a government programme to promote potable water savings by rainwater usage, there would be significant potable water savings and a consequent preservation of water resources in the state of Santa Catarina.