Methods of Assessment of Water Losses in Water Supply Systems: a Review

This paper reviews Water Loss Assessment methods in water supply systems. There’re three main methods: Minimum Night Flow (MNF) analysis, Bursts And Background Estimates (BABE), and Top-Down Water Balance. MNF analysis provides actual measurements whose accuracy can be evaluated. It requires intensive field work, though. The limitation of MNF application is the sensitivity of two parameters; average pressure which is rarely accurate, and estimation of the night consumption. Assessing real losses with the factors generated by the BABE model should not be conducted unless there is no other option due to its excessive assumptions. Instead, the method should be a supplementary tool to break down the volume of real losses into its sub-components. The Top-Down Water Balance is neither pressure-dependent nor extensive-field-work method. However, its assumptions of apparent losses aren’t appropriate for all utilities. The lack of an objective methodology for estimating unauthorized consumption is a major limitation, and research on its estimation is demanding.