The article estimates water usage in apartment buildings in Joinville, Brazil. They looked at 30 buildings to see how much water they used and how they were different. Buildings with individual water meters used less water per person than those with shared meters, about 34% less. Buildings with pools used about 48% more water per person than those without pools. On average, each person used 224 liters of water per day. Some buildings had different water systems, but their water use wasn't measured in this study.