Context and scope

This report was commissioned to investigate and clarify the potential causes of the unexplained 48% increase in water consumption in 2018 (2,336 m3) compared to 2017 (1,300 m3) of a building. The latter consists of 29 apartments with an ERS (Energy Reference Surface) area of 2180 m2, or an average of 75m2 per apartment. According to the technical sheets, we observe, for the neighboring building also consisting of 29 apartments but whose ERS is lower by 310m2, a consumption of 1386 m3 in 2018 similar to that of 2017 for the audited building.

Mission objectives and limitations

The purpose of this report is to provide a detailed analysis related to the increase in consumption which could be explained by the presence of leaks, a particular behavior of the different tenants in terms of water consumption and to provide a forecast of the consumption as of December 31, 2019 based on the data collected. This report includes the installation of the Droople solution (iSnap) on the main water meter at the entrance of the building. A measurement campaign carried out over a two-week period going from August 28, 2019 at 8:50 a.m. to November 09, 2019 at 1:04 a.m. with a frequency of one measurement every 10 minutes, i.e. 1943 measurements. The meter displayed a consumption of 13’995.9076 m3 at the start of the campaign and 14’069.3619 m3 at the end of the campaign.

This report focuses only on these two weeks of data and the historical data available via the partner report as well as the operating accounts for the last ten years. Therefore, it is in no way intended to replace a general water and energy audit.
The measurements were carried out with Droople measuring devices (iSnap), in particular the second version of the prototypes under development. As a result, Droople declines all responsibility for any errors or inaccuracies related to the results.

Results

Thanks to the measurements made on the main meter, we can conclude as follows:

• No leakage although there was a sustained consumption during the night of the 29th August to the 30th August at 7l / min or at more than 400l / h between 00:03 am and 04:07 am.
• An extraordinary event between 11:53 am and 06:17 pm with an average consumption of more than 1500l per hour. This outlier could be due to a technical intervention or to the watering of green spaces on this date. Concomitant consumption of several apartments seems unlikely to us over such a long period.
• The consumption at the end of the year would be between 1684m3 (<60m3 per apartment on average) and 1913m3 (<66m3 per apartment on average) or below the annual consumption of 2018 which was 2336m3. Based on the operating accounts, we note that in 2008, annual consumption was similar to that of 2018 (9,458.- CHF vs. 9,935.- CHF).