System leakage by night flow analysis: a case study in Guyana Available to Purchase

In the Caribbean, water utility companies widely acknowledge the high levels of non-revenue water (NRW). In 2004, Guyana Water Incorporated (GWI) implemented a project as part of the company's strategy to reduce water leakage. This paper reports on the use of bottom-up real loss assessment to estimate customer night consumption and background leakage for the test No. 56 district metered area (DMA) based on minimum night flow (MNF) analyses. The results from the test site show that leakage may be more than 50% of the supply. However, there is evidence that interrupted supply may affect estimates of MNF. Therefore, the results should be used with caution as water collection and storage during the nights can lead to overestimation of recoverable losses. To improve the results of similar studies in Guyana, testing should be carried out during the rainy season when there is increased availability of supply and the DMAs should be smaller with a greater number of individual consumption monitors.