A changing climate and environmental stress, growing populations in populous states, and evolving regulatory programs in many areas of the US are affecting supplies of water. Many utilities are now evaluating their water resources to determine how to stabilize supplies. Drilling new water wells, increasing water recycling facilities, and scrutinizing water loss to determine how it can be reduced are among the actions being taken by water utilities.
The focus here is on non-revenue water. The American Water Works Association defines non-revenue water as underground leakage that has gone undetected, plus leakage at storage tanks and leakage at customer metering. It also includes unbilled and unmetered water consumption, customer metering inaccuracies, unmetered and unauthorized water use, and systematic data handling errors.
AWWA has published its fourth edition of M36 Water Audits and Loss Control Programs. It has also published a 24-page White Paper The State of Water Loss Control in Drinking Water Utilities. Both are available online.
WATER IS UNDERVALUED
Bill Fahey, Veolia North America’s senior vice president for technical and performance, manages the technology staff for Veolia’s North American office. Veolia was established in France 160 years ago and is now active in 40 countries. Its business is in water and waste management and energy services. It operates and maintains water and wastewater utilities.
Non-revenue water loss is a most interesting issue, but oftentimes the cost to identify it and repair the infrastructure may be more costly than doing nothing, says Fahey. Water is extremely important to the planet, but it is undervalued, he explains. Utilities have to price their water in line with its true value. Investing in infrastructure is very important and water utilities need the revenue to renew assets as they deteriorate, he says.
When the utility is not charging enough for the water being distributed, it loses the ability to make repairs and institute ongoing leak detection and meter replacement programs, he continues. Utilities are always under pressure to keep rates at a minimum, especially in communities that can’t afford the investment in infrastructure required to repair and keep the distribution system up to date.
The technology is there but it is changing rapidly and becoming more complex, says Fahey. Data acquisition costs are coming down in this age of the Internet of Things. But a lot of communities can’t afford the technology. Furthermore, as demand goes up and water resources are strained, there is pressure to find leaks. This leads us back to the question Fahey asks: “How much money does one spend on a commodity that is undervalued?”
To understand their systems, managers should gather data and analytics, says Fahey. Begin with a methodology that looks at the utility’s assets, develop a good map of the distribution system, and determine the condition of these assets. Gather data and analyze it in order to focus investment on critical assets. Some points to consider: What are pump flows over the past five years? What are water pressures and noise? What are the changes in customers being served?
From a global point of view, municipal utilities find themselves in a perfect storm when it comes to non-revenue water loss, says Fahey. People are not investing in their assets and data analytics, the utilities are facing an aging work force, and training of staff is a challenge. There is limited state and federal aid available to assist utilities in these challenges and in repairing and replacing water lines, “But it is difficult for city leaders to get their arms around all of the complexities of utility investment for the future,” he says.
DELAYED MAINTENANCE LEADS TO LEAKS
The water department in New London, CT, was experiencing 35% water loss in 2005, according to Joe Lanzafame, the Director of Public Utilities. The cause was part accounting and part deferred maintenance, he says. He became director in 2009 and started an annual leak detection program which has been very successful, he says. Non-revenue water loss is now down to an average 14%.
How did the department do it? Lanzafame hired an experienced leak detection company to inspect the entire water system annually for water leaks and it utilized Veolia to immediately excavate and repair the leaks as they were discovered. The budget for this work is $20,000 per year.
The leak detection company uses high-tech correlators and listening devices to listen to valves and fire hydrants. (Speaker mics are attached on two different valves to listen for changes in sound that would indicate a leak. The correlator determines the location in between the valves, usually within 12 inches.) The detection company takes three weeks to cover both New London and Waterford—which the water department also serves.
As the detection company finds leaks, it provides a daily report to the department which assigns Veolia to repair it. Lanzafame says Veolia addresses the bigger leaks first, before the smaller ones. He stresses the importance of having people who understand how the distribution system works. The last inspection was in July and August of 2017 and the next one is due to start in November 2018.
“We’ve had leak detection companies come in that were not as effective,” says Lanzafame. It’s really important to find a really good experienced company, he adds, and to stay on top of potential water leaks. He has established a long-term relationship with the current company which knows the distribution systems of both towns and which understands the needs of the department. “Before, we were doing the inspections more frequently but with the comfort level we developed, we went to annual inspections,” he explains.
The City of Avondale in Arizona has identified production meters as a major non-revenue water loss problem. The meters were not measuring accurately due to design and configuration defects. One of the production meters at the Northside Booster Station is shown here being calibrated.
New London had been replacing its water meters on an accelerated basis every 10 years, but the strategy shifted. All of the old meters were gone after five years, says Lanzafame. And they found that the next generation continued to be accurate, so it was not cost-effective to replace them on the 10-year schedule. “It’s better that money is spent on fixing leaks and field repairs rather than on new meters that do not provide a significant increase in accuracy.”
Lanzafame says they’ve never been surprised by a large leak where the leaking water did not surface. “We know where there are significant water main breaks, as they will surface quickly.”
The water department distributes about 6 million gallons per day of water to the two cities, New London and Waterford, which have a combined 14,000 service connections.
MODERNIZING LEAK DETECTION
Matchpoint Water Asset Management Inc. was founded in 2005 to provide system deployment and integration solutions for water utilities transitioning from manual read to AMR/AMI. It is headquartered in Wilmington, NC.
The company now specializes in water infrastructure management and conservation services concentrating on data-driven solutions in partnership with innovative technologies developed and manufactured by other firms. “Leak detection services are Matchpoint’s core competency and we have executed hundreds of leak detection surveys using the acoustic investigative methodology,”
says Robbie Eisenrich, Director of Research Development.
In addition to its field services, in 2016 Matchpoint opened its Certified Technical Center in North Carolina to better serve clients by providing service, repair, and calibration of leak detection and network monitoring equipment, says Eisenrich.
Matchpoint partners with Esri using its Geographic Information Systems (GIS) to monitor potable and/or wastewater networks and retrieve data from monitored areas. It uses GIS to validate and computerize system information, such as valve, meter, and pipe locations, and makes the data available in GIS format for any software.
Recently, Matchpoint has developed the technique of using unmanned aerial vehicles, commonly known as drones, to survey areas of a water utility’s service territory to identify the general areas where unidentified, non-revenue water may be leaking underground. The drone, typically flying at 200 to 300 feet, is equipped with technology that looks for temperature anomalies. Eisenrich explains, “Anytime you have a point source, you pick up thermal energy which dissipates away from the source.”
Matchpoint then imports the images into Esri to map them using ArcGIS PRO. Eisenrich says they look for temperature patterns once they identify a candidate, then send out a crew equipped with acoustic listening equipment like loggers. To further locate the candidates, it uses Enigma correlators. A GPS locator may also be used to locate pipes, mains, or valves.
The City of Arlington, TX, was unable to locate two water leaks using traditional leak detection methods. It hired Matchpoint to use its UAV services to locate the leak using thermal imagery. It confirmed one leak occurring near the surface on a valve whose location had been unknown. Another leak was discovered along the length of a pipe buried 10 to 15 feet deep. The locations were hidden due to a lack of fittings in the vicinity as well as the low acoustic conductivity of the 16-inch concrete pipe.
The main issue is run time of a leak, says Eisenrich. Without a proactive approach, leaks may not be detected for a long time. District metered areas (DMAs), which divide a service territory into sectors, allow a utility to survey areas in a methodical, proactive way. Eisenrich says DMAs turn a utility system into a smart system. This leads to data-driven solutions.
Matchpoint has introduced its turnkey service where the client purchases monthly data. It will install insertion meters to collect flow and pressure data which identify areas of reduced system integrity. Then the company uses its traditional acoustic leak detection methods to further identify the area of the leak, says Eisenrich. This information is then turned over to the utility who will either repair the identified leaks or hire a contractor to make the repairs.
Eisenrich is eager to see further development in detection technology allowing equipment to communicate via cellular networks—i.e., city-owned Wi-Fi. “It could be a powerful tool that utilities could use in the future,” he says.
NEW TECHNOLOGIES AT WORK
The City of Abilene, TX, took a series of steps to ensure that it had a stable water supply during Texas’ historic drought. It invested $200 million in a number of projects, one of which was detecting water leakage in its distribution system.
In 2014, it hired a company to conduct a trial leak detection system using a fixed-based, non-intrusive aboveground technology such as repeaters to send data but no leaks were found. The water utility department reached out to Matchpoint’s Texas distributor, WL Prospecting (WLP), to perform a similar service. Matchpoint joined the project and committed to a 60-day trial leak detection survey.
After reviewing the earlier work, Matchpoint deployed 30 Phocus3 loggers, most of which were in drive-by mode and five were used as Lift-N-Shift loggers, manufactured by Primayer. The drive-by loggers were deployed within a five-block radius in the downtown area on 6-inch cast iron pipe located within the oldest parts of the water system.
Two leaks were detected within the 60-day trial. A leak within a fire hydrant was found using the “live” listening function of the loggers using headphones and a communications device. A much larger 6-inch leak on a cast-iron water main was found that went all the way around the circumference of the pipe and left no sign of leaking water on the surface. Furthermore, the leaking water was traveling out of the main and into a broken sewer services line. The department estimated that the fully pressurized 45-psi main had been leaking for about a year, losing a roughly estimated 40,000,000 gallons per month.
Once the loggers had highlighted the leak, WLP came back to perform a correlation using the Eureka3 real-time correlator. It identified the leak within 1 foot. WLP then deployed the Mikron3 electronic ground microphone system, also manufactured by Primayer, to guarantee the exact location for the excavation.
Wayne Lisenbee, director of capital improvements for the City of Abilene, who was assistant director of water at the time of the leak detection tests, says the savings, once the repairs were made, were difficult to identify because the length of time the leak lasted was unknown. The non-revenue water loss at the time was 6.2%, an extraordinary low rate. He says this is because the high clay content in the soil means leaking water will rise to the surface and the leaks are caught very early.
Lisenbee says the water department did not continue additional testing in 2014/2015. However, the city council in October approved an AMI program which will include leak detection.
GAS DETECTION FINDS LEAK
Breckenridge, CO, has a small water district where the normal water usage was around 25,000 gallons per day, but they were producing 90,000 gallons per day. The district contracted with Water Quality Control Professionals (WQCP) to help it lower their non-revenue water back to an acceptable level.
The contractor performed a leak detection survey. However, the system’s PVC main lines were located 12 feet below ground—a depth that made it almost impossible for the acoustic sensors to pick up sounds.
WQCP surveyed half of the distribution system where significant water loss was expected. They found a faint leak noise using an electronic listening stick. The contractor then deployed the Primayer Enigma non-real-time advanced correlation system to correlate on a 422-foot section of pipe where it produced a leak peak—signifying a leak was present—by using the narrow band filtering in the Enigma software. They found the peak was 167 feet from the Enigma.
To further confirm the leak location, WQCP talked to Matchpoint, which recommended using a Primayer PrimeTrace gas leak detection system. This system “sniffs” for leaks of gas (a mix of hydrogen and nitrogen), which are injected at an upstream service connection. After about 15 hours, the WQCP used the sniffer probe as they walked the target area. After reaching the pinpointed area, the PrimeTrace went into a high gas alarm telling them they had found the leak.
The use of these technologies saved the city $15,000.
CREATE DMAS
Suez North America has owned United Water since 1995, but only recently rebranded its name to match the corporate name. Suez NA owns some utilities and has contracts to run others. One of the utilities it owns is Suez Water New York where Nick Curcio is non-revenue water and business development manager.
Suez Water New York in turn owns and operates water systems throughout the state of New York. Curcio says the company’s experiences with non-revenue water loss fall under the overall strategy of sustainable management of resources.
Suez Water New York prefers to sectorize, or divide, a service territory into districts. “We can better identify where leaks are and can deploy services much more efficiently on the specific needs of the system in each district,” says Curcio.
Creating district metering areas (DMAs) is just one component of the company’s non-revenue water plan, in place since 2014. Each district is divided into sectors, and flow meters with data recorders measuring one-minute intervals are installed at each zone boundary. The consumption side is measured with high-resolution advanced metering infrastructure (AMI).
The next step is to develop high-resolution system performance information by comparing the amount of drinking water produced to the amount of water consumed as measured by the meters, says Curcio. This determines the amount of water lost in each district, whether it is non-revenue or apparent loss such as a customer meter failing, bill inaccuracies, or unauthorized connections.
Curcio says one has to determine where the losses are occurring. To determine whether and where water leaks are occurring, the data from each district’s meters must be analyzed for water usage variations, he says. A leak detection crew is sent out to correlate and identify as precisely as possible the leaks based on the clues developed from the analytics.
Finally, Curcio says, he recommends policies be developed and procedures and best practices put in place to prevent future water loss and increase efficiency.
Curcio says, “We also do pressure management throughout the system, where practical. It helps us to reduce unavoidable losses due to background leakage which are not practical to detect and repair.” They can add up along the system, he adds. Pressure management can control main break frequency and severity by reducing the overall stress on the system, which helps to promote longevity. There are fewer instances of breaks and associated damage as well as water loss within lower pressure zones, Curcio says.
Pressure management is conducted by carefully evaluating the system, Curcio says. “We cannot reduce the capacity to guarantee fire flow availability. Instead, we do hydraulic modeling to identify areas of the system which are candidates for pressure reduction. We cannot reduce the pressure below the measured requirement of 35 psi (in New York) and cannot reduce fire flow below standards developed by the Insurance Services Office, now part of Verisk.”
There are other beneficial consequences of pressure reduction. Flow rate reduction at non-volumetric fixtures promotes conservation surrounding most outdoor water uses such as lawn watering, Curcio says.
Large commercial and industrial customer meters account for 30% of total system water usage in Suez Water NY utilities but less than 1% of total meter fixtures. The “Strategic Metering Program” for these large customers monitors and tests meters on a more frequent annual basis and is more stringent than regulatory requirements to guarantee that they are operating correctly. This is to make sure customers’ meters are measuring consumption accurately, says Curcio.
Curcio talks about two of the company’s utilities and what they have been able to achieve. Suez Water New York in Westchester County had a non-revenue water loss percentage of 30% and was able to reduce it to a low 20% range and stabilize fluctuations to a more manageable degree. The reduction created reduced operating costs, he says, given that the utility purchases its water from other water authorities to serve that service territory.
New York regulations specify a maximum non-revenue rate of 18%. However, it is not system-specific and is based on a national average says Curcio. He makes the observation that every water system is unique and the economic impact of water loss could be different for each, concluding that 18% is not a universal number.
The Suez Water New York Rockland County service territory is hilly with elevation levels varying from 0 to over 1,000 feet. The terrain is very rocky and leaks surface less frequently in this type of terrain, Curcio says, resulting in more challenging conditions. The distribution system age ranges from 60 years to 85 years on average, Curcio says.
In Rocklin County, the utility was able to reduce the non-revenue water loss to the low 20% range. Curcio says, “If we have cold weather and a severe winter, there is an increase in breaks resulting in higher levels of water loss,” The age of the distribution system is approximately 50 years. He believes some of the company’s best performing assets are older. There is a low correlation between ages of the systems and line breaks, he explains. One consideration is the type of material and the manufacturer, plus the expertise of the installer and construction systems. Pipe vintage is much more reflective of asset performance than the general age of the system, which is a very poor determination of pipe condition and ability to meet service requirements, Curcio concludes.
United Water’s Suez Water Utility in its Westchester, NY-Division identified this leak using flow meters with data recorders measuring flows in one-minute intervals.
DESIGNING WITH AWWA’S M36
The city of Avondale, AZ, is in the middle of the Sonoran Desert at the confluence of three rivers—Tres Rios—and immediately next door to Phoenix. Of course water is an issue in that region, and as Lacey James, Water Resource Manager for the city, says, “The tighter we can get water down, we save another bucket of water.”
In 2017, the city delivered 12.7 million gallons of water per day. It has six storage sites with a total capacity of 8 million gallons per day and six booster pump stations with a capacity to pump 59 million gallons per day. It serves 24,500 individual customer accounts.
James says she and her team are in the beginning stage of designing a water leak program designed along the lines of the AWWA’s M36 program guidelines. The Arizona Municipal Water Utility Association is partnering with the city and is helping to get the city some grant money to start a pilot.
In the meantime, to get started, the city put together a team with representatives from the water billing department, the non-revenue water team, the meter department, the water distribution staff, and water production staff. James says the communication has been really successful.
The team has been looking into the non-revenue water numbers and James says most of the numbers indicate a data issue and a production meter issue at well sites. The meters at 15 production wells were located on pipes and the piping design and configuration caused problems. The old propeller meters weren’t measuring accurately and will be replaced, she says. The city has applied to the Bureau of Reclamation for a small-scale water efficiency project grant to replace some of the piping and to change out the meters.
The water distribution team has an annual leak detection program covering 321 miles of water main lines, according to Leonard Moreno, the department’s Water Distribution Supervisor. Using the Gutermann Aquascan correlator and Aquascope ground mic leak detection equipment, his operators have found small leaks that are coming from the main valve on dry barrel fire hydrants. He says, in an email, last year approximately 25 leaks were located but were not visible from the surface of the ground. Approximately $10,000 was spent to repair these leaking hydrants in the last fiscal year, not including time and labor costs.
James hopes to expand the non-revenue water loss program beyond what the distribution team has been doing. The city has put very little into non-revenue water loss program, she says, and this is why she is so enthusiastic about AWWA’s M36 program and to build a more comprehensive water loss detection program.
STRICT REPLACEMENT POLICY
Pasadena has no significant real losses, says Ursula Schmidt, Pasadena Water and Power’s water conservation program manager. Instead, the water department has an active and ongoing water main replacement program and it replaces consumer meters every 15 years.
The city has 520 miles of water mains which delivered 28,806 acre-feet of water in 2017. The Water Department calculates that it has 2,300 acre-feet of both real and apparent water loss, says Schmidt. Real losses were measured at 1,845 acre-feet, approximately 6.4% of total distributed water. Real losses include leakage on transmission and distribution mains, leakage and overflows at utility storage tanks, and leakage on service connections up to the point of customer metering.
The water main replacement program is designed to replace 3 to 8 miles of main pipe every year. At this rate, the entire water main system will be replaced every 100 years, Schmidt says.
Schmidt says the reason the water department has very little non-revenue water loss is that first, the soils or water are not very corrosive. She also attributes the water main replacement program as keeping ahead of underground water leaks.
The water department has 14 water reservoirs and 17 wells. The reservoirs are checked regularly and cracks are patched when found. When a customer reports a problem, perhaps on a bill, the department checks weekly reads and if something appears off, the customer’s meter is checked, along with the pressure at the point of connection.
Schmidt says the department’s budget for 2017 is $11 million for the water main replacements; water meter replacements; and repairing and replacing meter boxes, vaults, and steel plates.
