Preventing Revenue Loss through Leak Detection
The Advantages of Implementing an Integrated Water Loss Management Plan
Morrice Blackwell May 18, 2012
Utilities across the nation are facing a growing problem. Aging water delivery systems, coupled with tighter local and national budgets, are leading to infrastructure failures. Among the problems are leaks and older meters that are losing their accuracy due to a lack of maintenance or needed replacement. As a result, non-revenue water has become a considerable concern, and locating the true source of water loss has become a top priority.
Municipal water loss can cause a host of problems for utilities in both the short term and long term. It expedites the rate of infrastructure damage and wastes the energy and chemicals used to deliver and treat water. Even more importantly, water loss has a significant impact on utilities’ bottom lines. The Environmental Protection Agency (EPA) estimates that leakage from water distribution systems costs the U.S. one to two billion dollars annually – a figure that grows exponentially when taking into consideration infrastructure repairs and property damage.
“Every utility has some leaks within its system,” said John Fillinger, marketing manager at Badger Meter, a provider of flow measurement technologies and solutions. “The issue is that even a small leak, say it’s a service line of just one gallon of water per minute, will end up costing you 525,000 gallons of lost water each year. And, that’s water you’ve already paid to treat and deliver.” Therefore, it’s more important than ever for utilities to consider a water loss management program.
Leak Detection Methods
There are two categories of water losses: real losses and apparent losses. A real loss is essentially a leak where water is physically lost and never reaches the end-user. An apparent loss occurs when water is delivered to the end-user, but the utility is unable to bill it, often as a result of metering inaccuracies or theft. Fortunately, advances in technology are making it easier for utilities to detect and isolate water losses so they can deal with issues quickly. For example, when combined with leak detection monitoring technology, the increasingly popular Advanced Meter Reading (AMR)/Advanced Metering Infrastructure (AMI) and the new Advanced Metering Analytics (AMA) systems offer a powerful defense.
“Connecting leak detection and monitoring technology with AMR, AMI and now AMA capabilities provides utilities with near real-time data to allow them to detect and respond to leak alerts before they turn into large-scale problems,” Fillinger said. “It’s that proactive approach that mitigates water loss and revenue loss.”
Leak Detection Sensors
Standard leak-detection technology includes acoustic leak detection sensors. Here’s how it works: Sensors are magnetically connected to the valve key on the water main valve at various intervals on a distribution system. Spacing depends on the type of pipe. Sensors on metal pipe systems are spaced approximately 1,000 ft apart, as these pipes allow for better acoustic vibrations, while sensors on PVC pipes are spaced about 500 ft apart.
“After establishing a baseline of normal acoustic noise, the sensors are able to pick up any anomalies,” Fillinger said. “Each night between 2 a.m. and 4 a.m., when the system is normally at its most quiet state, the sensors will automatically ‘wake up’ and ‘listen.’ If the system detects something is off the baseline, it will record that as a potential leak. After one hour, it will ‘listen’ again.”
If the sensor detects noises outside the norm again, it will send out an alert to indicate there is a potential leak. This is called “leak surveying” and it is where AMR/AMI technologies can provide utilities with added speed and efficiency that leads to more savings.
“Integrating AMR/AMI allows for an almost instantaneous response in finding out where your leaks are,” Fillinger explained. “So if a utility has a mobile AMR system, they can connect the sensor to an AMR module. Then, as meter readers are out on their normal routes, they are also able to pick up on the acoustic leak detection sensor readings as well.”
Once the leak surveying process has alerted the utility of a potential leak, the utility can then pinpoint the leak with the use of precision correlators or ground microphones. In a fixed network environment, utilities can pinpoint potential leaks remotely and then investigate further with ground microphones. “The quicker you find the leaks, the quicker you can repair them and the more money you are saving,” Fillinger said.
District Metering Area
Another effective leakage control methodology is a District Metered Area (DMA), sometimes called a District Meter Zone (DMZ).
“A water distribution system is looped so that if there is a break in front of one home, utilities are able to turn off the valve to isolate that break to repair it, and it doesn’t stop all water downstream,” Fillinger said. By “valving off” neighborhoods with DMAs into separate areas, utilities are better able to pinpoint where the water loss is occurring and then take action to resolve it.
In a DMA, a master meter allows utilities to monitor the amount of water going into a given isolated area. Utilities can compare this reading to the aggregate of metered services in that zone. If there is a discrepancy between the amount of water the master meter reads and the total of individual meter readings for services in that area, it signals a potential issue. Because many utilities still employ the older metering technology, the root of the problem may not be a leak in the infrastructure; it could be the meters.
“The make-up of traditional meters, which use mechanical movements to measure water, means that accuracy rates may decrease over time due to friction and wear,” Fillinger said. “This type of distribution inaccuracy generally needs to be resolved by replacing the meter itself. Since not all meters are created equal, utilities need to carefully consider the metering solution deployed to increase and maintain accuracy of the system.”
Bridging the Informational Gap: AMA Provides Additional Efficiency
Last year, Badger Meter introduced a new player into the AMR/AMI mix. Advanced Metering Analytics, or AMA, takes the information AMR/AMI provides to the next level.
“AMA plays a huge role in rapid water leak detection, because it enables utilities to uncover distribution system leaks through continual usage flags, acoustic leak detection and observation within the district metering areas,” Fillinger said. “It’s flexible in that it allows the utility personnel to set up the business rules that they want to monitor.”
Fillinger also said that if there is a slight discrepancy between the master meter and the aggregate measurements, utilities can program the system to alert them when that amount exceeds certain points. “This means utilities won’t have to manually run reports – AMA automatically does it for them and will alert them if needed,” he said.
As the pressures of limited economic resources and water shortages mount, water loss is becoming a critical issue for many utilities. However, with an integrated water loss management plan in place, utilities can lower the occurrences and mitigate costs of both real and apparent losses. More sophisticated AMR/AMI data-gathering systems combined with the proactive elements of AMA are vital in helping utilities identify and fix leaks, preventing infrastructure damage and revenue loss.
Morrice Blackwell, marketing manager at Badger Meter, is an expert in flow measurement, automated meter reading technology/networks and utility management for the water industry.