Using Statistical Control Charts to Monitor Building Water Consumption: A Case Study on the Replacement of Toilets

This manuscript proposes the usage of Statistical Control Charts (SCC) to monitor water consumption in buildings. The charts were employed to study the impact of replacing toilets, providing visual and statistical feedback to measure the efficiency gain resulting from the replacement of outdated flushing equipment with newer devices. The case study was conducted in a building from a university in the South of Brazil. The building has four restrooms, from which a total of 41,554 readings were collected during a 15-month period using digital water meters. After the toilets were replaced, a reduction averaging 30.22% in water consumption was observed (from 7.51 L/flush/day to 5.24 L/flush/day). Additionally, the control charts were able to pinpoint dates when unique events happened during the water-consumption monitoring process.