WATER LOSS MANAGEMENT IN NORTH AMERICA - JUST HOW GOOD IS IT?

摘要

A 1996 overview of water production and delivery statistics, in 469 US Water Utilities, showed Metered Water Ratios averaging 84%, implying Unaccounted for Water (UFW) of 16% of production, on average. The range of UFW was very large, from over 50% down to 1%, with a 13% modal (most frequently occurring) value. So how does this compare to other countries worldwide? An international data set of 27 systems from 20 countries, assembled by the International Water Association Task Force on Water Losses which included two of the authors, showed a range of Non-Revenue Water (NRW) from 2% to 40%, with an average of 17.5% and a 13% modal value. These overall statistics seem fairly similar. However, technical committees in many countries - including the AWWA's Leak Detection and Water Accountability Committee - have realized over recent years that expressing UFW or NRW as a % of production is only a very crude measure of true performance in managing water losses, because it is strongly influenced by differences in consumption. The IWA Water Losses Task Force, working in conjunction with an IWA Task Force on Performance Indicators, has recently reviewed the traditional measures for comparing UFW/NRW/Water Losses. They recommended improved measures for comparing performance, applicable to a wide variety of different situations between, and within, countries.