This article provides water utility managerswith guidance on alternative measures ofwater use and how these measures, or metrics,can be most appropriately used for comparingand evaluating water efficiency. There is currentlyno universally perfect metric for describingwater use, but several metrics are betterthan per capita use in terms of the availabledata's accuracy and informational value.Water utilities and regulators have anincreasing need for meaningful performanceindicators and benchmarks for measuring andcomparing water use. Significant improvementsin the ability of water utilities to reduce"definitional noise" in monitoring and comparingwater usage rates would be achieved ifthe water supply industry adopted a standardset of customer types and customer classificationprocedures.Available water production and salesrecords can be used to calculate both systemwideand sector-specific metrics of wateruse. For a systemwide metric, the only accurateand regularly updated measure of systemsize is the number of connections orcustomer accounts.Includes 12 references, tables, figures.