Impacts of meter aging on water meter measurement errors and assessment in the context of apparent losses management

Water losses, defined as the difference between the total water volume supplied to water distribution systems and the legally consumed water volume, are classified as real and apparent losses. Real losses occur due to leaks in drinking water distribution systems, service connections, and tanks, while apparent losses arise from unauthorized consumption and metering errors. Apparent losses result from metering errors in well-managed water distribution systems are the component of water losses where water delivered to consumers but not accounted for economically. Metering errors in water meters occur as meter age and prevent fair pricing by decreasing measurement performance. This study aims to investigate the effect of meter age on measurement errors and to evaluate this effect in the context of apparent losses management. Within this scope, the starting flow rates and measurement errors under different flow rates and pressure levels were analyzed for 490 multi-jet water meters, aged between 1 to 12 years, used in the Antalya. Water consumption of 50 representative users was monitored to determine the flow rates for testing, and their consumption profiles were established. These profiles were used to calculate weighted measurement errors. The study concluded that starting flow rates, measurement errors, and weighted errors increased with meter age, although the increase was not linear. The rise in starting flow rates with meter age was more pronounced in meters older than 8 years, while measurement errors and weighted errors showed a significant increase after 6 years. For meters aged 1-5 years, measurement errors and weighted errors did not vary significantly under different pressure levels, whereas meters aged 6-12 years exhibited differences between low and high pressure, indicating that pressure affects aging meters. It was also found that the measurement errors associated with older water meters are predominantly negative. These negative errors increase at low flow rates as meter age increases, meaning that the water used by consumers is under-registered, which contributes to apparent losses.