Metering Minute: Better Ways to Eliminate Water Loss

Metering Minute: Better Ways to Eliminate Water Loss

By Laura Wainwright

Non-revenue water loss is a constant concern for water utilities. Not only do utilities lose money when water leaks into the ground, but the loss negatively impacts water-resource management efforts. Until recently it was extremely difficult to accurately pinpoint the position of suspected leaks, even when using field-correlation methods. However, promising acoustic leak-detection technologies combined with proven fixed-network solutions are making accurate, correlated leak detection a reality.

Several acoustic technologies can be used to discover potential leaks within a public water system. Some collect data at the meter while others work at the main or the rate-control station. How closely a leak is pinpointed, however, depends on how the acoustic data collected is analyzed.

Typically, the logging devices used to sense acoustic changes in the water system provide only the approximate location of leaks. Those used at the meter, for example, take a reading and send a specific number back to the utility that indicates the likelihood of a leak in a fairly large area. The utility must physically survey the suspected area of the leak using special equipment and then correlate those readings to pinpoint its exact location.

These in-home devices can greatly improve the chances of finding leaks before they become huge problems, but loggers located on the main take leak detection to the next level. Devices at the main provide a sound recording that allows experts, who can often tell if a leak is present just by listening, to hear a leak from the home office. This eliminates the need to send a crew out to the field to analyze the sound on the main.

What's more, devices located at the main provide enough data back to the utility so that correlation software can be used to pinpoint leaks, sometimes within a few feet or meters. Adding information about the physical properties of the system to the software model, such as materials used for pipes, improves correlation results even more.

Automatically collecting the data from leak-detection units via a fixed-network solution literally closes the loop on the system by allowing correlation without any field work. While not eliminating the need for experts to analyze data, a fixed-network system simplifies data collection and allows utilities to schedule readings for convenient times, such as early morning hours when loads on the system are lowest.

Finding and fixing leaks before they surface helps utilities save tremendous amounts of time and money and improves water-resource management and conservation efforts. In the future, water utilities will find acoustic leak detection combined with a fixed-network solution the most accurate and cost-effective way to eliminate non-revenue water loss.

Laura Wainwright is a product manager with Hexagram Inc. (http://www.hexagram.com; Cleveland, OH), a supplier of innovative fixed-network AMR systems to meet the ever-changing needs of municipal and investor-owned utilities.