The percentage of non-revenue water compared to water fed into the network is related to physical or real losses (due to breakage of pipes or hydraulic equipment, etc.) or procedural or apparent losses (metering inaccuracies, errors in estimated presumed consumption at 31 December, unrecorded internal consumption, illegal use). The latter losses result in water which is effectively delivered to the final customer but is not recorded or billed.
Until 2006, network losses were calculated as the difference between the water fed into the water network during the year and the water accounted for as supplied to customers during the same period: the amount was estimated at 31 December of every year on the basis of the historical consumption of customers since it is not possible to take a single reading at 31 December of all the meters. This estimate was then supplemented so as to take into account the correct period of recording in accounts of the water sold to customers as at 31 December of the previous year, calculated after reading all the meters. Since 2007, network losses have been calculated by integrating the adjustments coming from meter readings in the pertinent year, thereby ensuring perfect comparability between water sold and the related amounts fed into the system each year. With this approach, it is possible to calculate the final figure for the year only around 4-6 months after the close of the financial statements, or after all the meters have been read. For this reason, the table below does not include the provisional figures for 2017.
At Group level, network losses for 2016 were 31.6%, in line with 2015. The Group continues to rank significantly below the national average of 39.1% in 2016 (source: Istat, Dati ambientali nelle città 2016) and the 35% average of the 12 largest provincial capitals (source: Legambiente Ecosistema Urbano 2017).
The corresponding line loss for 2016 is 10.3 m3/km/day, in line with 2015. We believe that the figure of water not billed per kilometre of network is more representative of the effectiveness and efficiency of the distribution system and more useful for comparison with other companies. The figure for line losses in the Emilia-Romagna region was 9 m3/km/day in 2016, substantially in line with the average of 8.3-8.4 m3/km/day measured by the European Environment Agency on a group of 32 European utilities that took part in the study “Performance of water utilities beyond compliance”. It is an even more significant value if compared with the average of 27 m3/km/day of the major Italian utilities for 2016 (source: Utilitatis, Benchmarking della Sostenibilità 2017).
The figure for 2017 is not reported since it is provisional.