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Feature the distribution network, via leakage from mains, services, and storage tanks. Apparent losses are economic, nonphysi- cal losses that result from underregistering customer meters, underbilling of customers, and theft. Imbedded into the Water Audit Method is the Data Validity score — a measure of confidence and reliability in the Water Audit outputs. Data Validity must be your first consideration in using the Water Audit to guide water loss management activities. Systems with low Data Validity scores must focus next steps on improv- ing data. Those with high Data Validity should focus next steps on reductions in water loss. Those with medium Data Validity scores must examine closely to determine the appropriate balance of next steps for data improvement and water loss reduction. All systems have water loss, and all systems have some of each component — real losses and apparent losses. The big question is how much of each, and what are the cost impacts of each? This is central to any effective strategy. Consider the importance of applying the right strategy to the right problem. How effec- tive will implementing a comprehensive customer meter testing and replacement program be for solving a leakage prob- lem? How about an active leak-detection- and-repair program for solving systemic billing system issues? And consider the cost effectiveness of any strategy, even if it's the right tool for the job. Are we spending a $1,000,000 on a $500,000 problem? An effective strategy — for both results and cost — must match the problem in both scale and nature. State Of The States In 2002, an analysis 3 of state agency water loss reporting practices was con- ducted by Beecher Policy Research, Inc. Two primary conclusions came from this survey — the first was the wide- spread use of the performance term "unaccounted-for water percentage" and the second was a clear inconsisten- cy in what was considered "acceptable loss" (see Figure 2 on page 10). AWWA has long since denounced use of the imprecise term "unaccounted-for water" (UFW), as well as percentage-based metrics, as they have been deemed inconsistent and unreliable as per- formance measures. UFW has been abandoned as an "old technology," joining the likes of the 8-track and rotary phone. In its place the IWA/AWWA Water Auditing Methodology, as defined in the M36, Manual of Practice for Water Audits & Loss Control 4 (M36 method), is recognized world-wide as best practice in the industry for the accounting and control of losses in drinking water systems. Central to the M36 method is the rational segregation of real (physical) and apparent (economic) losses and analysis of the components of each type of loss, which informs an effective control strategy. An analysis 5 in 2005 on water loss policy and regulation 9 wateronline.com ■ Water Online The Magazine 8 _ V E R T _ 0 5 1 4 C l e a n w a t e r _ C a v a n a u g h _ D G . i n d d 2 8_VERT_0514 Cleanwater_Cavanaugh_DG.indd 2 4 / 2 1 / 2 0 1 4 2 : 5 6 : 2 7 P M 4/21/2014 2:56:27 PM