The impact of incorrectly sized bulk meters on water consumption and municipal revenue

Abstract

South Africa is a water-scarce country, characterised by lower-than-average rainfall and high water consumption rates, with Non-Revenue Water increasing despite water conservation efforts. Literature shows that bulk water meters are often incorrectly sized, increasing Apparent Losses from metering inaccuracies, resulting in revenue loss and negating the municipality’s water conservation and water demand management initiatives. This study investigates the impact of incorrectly sized bulk water meters (sized 40mm – 150mm installed at non-residential and multi-residential facilities) on municipal revenue by analysing flow logging data and metered consumption characteristics of 42 users. The methodology combines flow logging to analyse actual water consumption characteristics, assessment of meter operating flow ranges for optimal sizing, calculation of weighted accuracy for Apparent Loss estimation, and literature review on meter sizing and alternatives to consider regarding fire demand requirements. Highlights from this study are (a) the consumer profiling findings underscore the importance of aligning meter size with consumer water use patterns: consumption below the meter’s starting flow is observed at 50% of the stands analysed in the dataset, indicating over-sized meters; (b) 57% of the stands had on-site leakage, occurring at low flow rates where meters are most inaccurate; (c) two examples demonstrate the impact of incorporating fire demand, resulting in meter size changes from a 15mm to 100mm, and a 25mm to 150mm, respectively; (d) resizing meters for 35 stands is estimated to result in an additional municipal revenue gain of R636,876.92 within one year. Overall, the study highlights the importance of accurate meter sizing for reducing Non-Revenue Water, improving revenue generation, and enhancing water conservation efforts.