This paper compares the methods for sizing rainwater reservoirs for non-potable uses provided by the Brazilian Standard NBR 15527/2007 and the Municipal Decree 293/2006 in the city of Curitiba, state of Parana (PR), in the south of Brazil. To pursue that objective, five rainwater harvesting systems located in buildings in the city of Curitiba were studied. The results obtained from those two methods varied significantly. In order to obtain volumes that are consistent with the harvesting of rainwater, the Municipal Decree equations should be revised in order to include rainfall data, roof size and the rainwater demands in their formulation. Standardization of the names of the variables is suggested for the methods described in NBR 15527/2007, as well as the inclusion of more information about its equations, since the existing ambiguities may lead to misunderstandings. In order to decide on the best method, one should compare the different results and evaluate the available area for the construction of the reservoir, as well as its cost.
Curitiba; Municipal Decree 293/2006; NBR 15527:2007; PURAE; Rainwater; Sizing
