Dataloggers are devices placed temporarily on a water meter to record the flow. The data is later downloaded onto a computer with software that displays the data in a common format, such as an Excel spreadsheet. Reports can be generated indicating the flow in various time intervals, such as every minute or every hour. Irvine Ranch Water District has been using these devices to determine the correct water usage for numerous commercial customers. The results of the datalog reports have been helpful in winnowing out indoor from outdoor usage and, to some extent, consumption of selected process equipment. In this manner IRWD has been able to determine the presence of leaks, even after the customer has had the absence of such leaks verified by a plumber. IRWD has also been able to discover instances of overwatering and ascertain when equipment is operating at levels higher than suggested by the manufacturer. Although the datalogger reports cannot record where the water went, by knowing how much water was used and at what time of day, the user can often make highly accurate guesses. This paper presents a sampling of case studies.