Customer water meter accuracy under various field conditions : case study NWSC-Kampala water Uganda

Abstract

One of the impending factors affecting water utility's ability to supply adequate and safe water worldwide is high water losses. Inaccurate metering contributes greatly to the apparent losses in many water supply utilities, including the National Water and Sewerage Corporation (NWSC). This research presents a platform for understanding the contributions of metering inaccuracies to non-revenue water while investigating the perceived effectiveness of establishing best technical practices and strategies for decisive selection, installation, and management of customer water meters to minimise losses. The study had three specific objectives, including; (i) Characterising the pressure rates in the distribution network of the study area. (ii) Assessing impacts of meter class on its performance accuracy (iii) Determining the influence of working age on water meter registration errors (iv) Producing geo-visualised pressure rate zoning maps for the water distribution network in the study area. Pressure data loggers were installed at selected customer premises and results were downloaded using Radwin software. Randomly selected sample water meters from the total population were collected from the field and subjected to different tests under different flow rates and pressure using a meter testing bench. The test results were analysed using descriptive analysis to obtain the favourite condition for better meter performance. To produce meter risk visualisation maps ArcGIS software was used. Using obtained pressure, meter age, and meter class test results, meter failure risks was georeferenced and visualised maps obtained. The pressure test results show pressure > 60m and < 10m in Kansanga and Kyengera respectively with an average of 70.2m and 42.1m maximum pressure. Water meter performance test results revealed better performance (3%) of meters at a flow rate of 1500 l/hr with a pressure rate of 5 bars and poor performance (- 7%) with a flow rate of 12 l/hr at 10m pressure rating. Meter age beyond 15years performed poorly at low flow rate. This implies that most water meters are dysfunctional at low flow and pressure rates, causing losses to water utilities. Meter age and meter class had significant (p<0.05) impacts on meter performance accuracy. Meter risk analysis and visualisation revealed blocks with water pressure and age risks on meter performance. The study recommends proper management of meter installations based on pressure zoning and flow regimes. The results of this study were pertinent in providing support policymakers in relation to forecasting and strategic development of robust metering systems that prevent meter dysfunction hence reducing non-revenue water.