The apparent losses due to metering errors: a proactive approach to predict losses and schedule maintenance

The effects of water meter age and private tanks on the apparent losses due to metering errors were evaluated by experimental and theoretical analyses. A monitoring campaign on a small district metered area (DMA) was carried out to determine the causes of apparent losses and implement a numerical model. Metering errors are affected by the flow rate passing through the meter, which is dependent on the network pressure and water level of the private tank. A node model that reproduces the effect of private tanks was coupled with EPANET and was applied to the DMA. The proposed modelling approach was used to identify where apparent losses are higher and to schedule maintenance. The model predicted the results of the installation of a device that minimises the effect of private tanks on apparent losses, the unmeasured flow reducer (UFR), the economic impact of losses and substitution programmes.