Identifying opportunities for revenue recovery through improving drinking water loss efficiency using AWWA M36 methodologies in the Dedham Westwood water district

Abstract

The goal of this research is to eliminate Unaccounted for Water (UAW) using the American Water Works Association's (AWWA) M36 audit approach and identify new sources of revenue for the Dedham-Westwood Water District utility through increased operational efficiency. Although a specific utility is used in this study, the approach is intended to be applicable to most water utilities. This research uses American Water Works Association's (AWWA) M36 Water Loss Control program recommendations to increase the utility's self-reported data validity scoring from 69 to 74. First, the accuracy of the volume supplied to the distribution network was verified by accounting for master meter supply errors. Second, the total authorized consumption volume was quantified by differentiating metered or unmetered consumption, which is either billed or unbilled. Next, total water loss was divided into apparent and real losses. Apparent losses are defined as non-physical and include customer meter inaccuracies, systematic data handling errors and unauthorized consumption. After apparent losses were defined, real losses, otherwise known as leakage, were identified by subtracting apparent losses from total loss. This is contrary to the industry standard water loss tracking methodology where total loss is assumed to be real loss and only pursued through leak detection. The 2017 baseline utility self-reported total loss was 241.3 MG, assumed to be completely due to leakage, and therefore evaluated at the variable production cost of $670/MG for a total value of $161,400. Using AWWA M36 methodologies, the data validly of the baseline utility self-reported total loss increased by 25.8 MG through accounting for master meter under registration. Next, this increased total loss was further divided into apparent and real losses, where apparent loss was further sub divided into 48.2 MG of customer meter inaccuracies, 4.0 MG of unauthorized usage, and 3.1 MG of systematic data handling errors. As part of this study, apparent losses were evaluated at the customer retail rate of $7,830/MG, as these losses occur at the point of sale, for a total value of $433,000. After deducting apparent loss, the remainder of total loss was assumed to be real loss, totaling 211.7 MG and evaluated at the variable production rate valued at $141,800. Thus this study effectively identified $575,000 of loss to recover. The study concludes with recommendations on pursuing apparent losses prior to real losses due to a higher unit cost and generally less expensive costs to recover. The findings from this study suggest that drinking water utilities can identify an optimal strategy to reduce losses, increase operational efficiency and recover revenue by following AWWA M36 loss recovery using methodologies. I