**3. Results**

### *3.1. Water Consumption and End-Uses*

The average daily consumption obtained from the water meter was 612.9 litres/day. Based on this consumption and considering that there are 31 days in August, an average monthly consumption of 19.0 m<sup>3</sup> and an average per capita water consumption of 153.2 litres/person/day were estimated. Based on the results from the questionnaires, the consumption was estimated as 3678.9 litres over the period analysed, which is equivalent to 131.4 litres/person/day. Over August, the monthly consumption would be 16.3 m3.

Water consumption measured by the company responsible for water supply in the city of Blumenau was 21 m<sup>3</sup> in August, when the study was conducted. This volume is 10.5% greater than the estimated consumption. From April to October 2019, consumption varied from 14 to 22 m3, with a monthly average of 18 m<sup>3</sup> and equivalent to an average daily consumption per capita of 145.2 litres/person/day. Therefore, water consumption when the data were obtained was not atypical.

The difference between measured and estimated consumptions varied from 4.0 to 22.6%, with an average of 11.0%. Such differences may have occurred because of errors in the durations' records and/or because the residents failed to note some uses. One considered that the difference between the estimated and the measured consumptions was evenly distributed among the water fixtures. Thus, the water end-uses were based on questionnaires filled in by the residents. Table 1 shows the water end-uses for an actual house. The water end-uses are similar to those obtained by Freitas [15] and Meincheim [13] studies. The water fixtures with the highest consumptions in single-family homes were the shower, washing machine and toilet.


**Table 1.** Water end-uses for an actual house.

### *3.2. Rainwater Demand*

The rainwater harvesting system was designed considering rainwater usage only for non-potable purposes (washing machines, toilets, outdoor taps and washing troughs). Therefore, based on the water end-uses of the actual house, the rainwater demand represents 59.3% of the total water demand. According to this result and the literature review, the different scenarios considered rainwater demands equal to 30%, 40%, 50% and 60% of the total water demand. For each scenario, a lower tank capacity was estimated, while the upper rainwater tank capacity was calculated based on the total rainwater demand.
