Pressure Zone Audits Pinpoint Water Loss

Abstract

This article discusses how automatic meter reading (AMR) with data‐logging functions and hourly system comparisons allow utilities to analyze new levels of detail in system supply and customer demand. This information helps utilities better understand water losses and whether the losses result from inaccurate meters, system leaks, or water theft. The article offers an example of California's East Bay Municipal Utility District evaluating the conservation benefits of mobile and fixed‐network AMR systems, equipped with data‐logging capabilities, in two pressure zones known as Round Hill and Holly. The goal was to determine the true nature of lost water – leaks, flushing, fire flow, system meter error, customer meter error, theft, leaks from one zone to another, or any combination of these factors. In addition to AMR and data‐logging‐equipped customer meters, the audit used historical hourly supervisory control and data acquisition (SCADA) operations data for flow rates and reservoir level indicators, acoustic leak‐detection equipment, and customer‐meter testing equipment. Audit details are provided, along with study findings. Field tests revealed that apparent losses are evident from graphical analysis. The leakage survey revealed no significant distribution system leaks within the pressure zones. Slow customer‐side leaks, especially on large meters, are sleeping giants of system loss within pressure zones.