Editor’s note: This article first appeared in the January/February 2015 edition of Water Efficiency.
Non-revenue water is a hot topic in the water treatment and distribution industry. If water utilities were charities, they would be expected to give their water away for free, and if water wasn’t so difficult and expensive to process in the first place to make sure it is safe for human consumption, then it wouldn’t matter if millions of gallons “disappeared” from the system as a result of leaks. However, water utilities are not charities, and water treatment is not an inexpensive process. As a result, it is incumbent upon every water utility to make sure that as little water as possible is lost from its system, and to make sure that every gallon that is provided to customers is properly billed for.
Here, we look at a number of programs that have been incredibly successful in reducing water losses and reducing non-revenue water.
While United Water has always had a commitment to reducing its water losses, the company recently adopted a new initiative focused on sustainability and being environmentally friendly, which, of course, involves keeping water losses to a minimum. “Water is such a valuable resource that we want to make sure we are doing everything we possibly can to ensure that non-revenue water is a top priority,” says Lynda DiMenna, manager of United Water New Rochelle-Westchester.
Nick Curcio, United Water’s non-revenue water manager, explains the concept behind the new initiative and the role that non-revenue water management plays in it. “We put a certain amount of water into the system at certain points and get less out on the other end when we bill our customers,” he says. “The difference between those two numbers is what we call non-revenue water–water supplied to the system that does not produce revenue at the customer meter points. There are many ways that water can be lost. We needed to characterize and measure those components before we could take any action aimed at reducing that loss.”
The first step for United Water is to generate and collect information in order to evaluate the nature of any water loss. One effective way to do this is to divide the larger distribution system into smaller, more manageable sectors that can be viewed independently as their own water systems. In this way, United Water created a District Meter Area (DMA) sectorization program for its New Rochelle-Westchester system, dividing it into eight smaller subsystems or zones, and then identifying, based on flows entering and exiting the zones, the amount of water that remained in each one of those individual zones. “When we can compare this against our consumption data, it helps us identify zones where water losses are at higher levels, and then we can focus resources on those zones,” says Curcio.
|Credit: MODERN ELECTRIC WATER CO.
Finding and repairing leaks is a never-ending challenge.
Creating these new zones, of course, required new sector meters to be able to measure water in and between them. “We looked at a number of different vendors, and Siemens Industry had the technology and the support that we were looking for,” says DiMenna. “We found that their technology provided the best accuracy in terms of capturing and measuring every type of flow range that we were expecting at the different sites, including high flow, low flow, and reverse flow.”
In years past, according to Brian Roughan, senior account manager for Siemens, the accuracy of mechanical meters was plus-or-minus 1.5%, which was acceptable at the time. Over time, with build-up, the accuracy decreased even more. “As a result, utilities had to pull these meters out every six months or so to have them calibrated in the lab,” he says. “However, as state requirements came into existence related to water loss, accuracy began to become more important.”
About eight years ago, Siemens came out with a battery-operated magnetic meter that has no moving parts to affect the accuracy of the meter. The stated accuracy rates are between plus-and-minus 0.2 and 0.4%, and, unlike mechanical meters, these meters do not need to be pulled out to be recalibrated. There are two battery options. One is an internal battery that needs to be replaced every six years. The other, and the one that most utilities select, is an external battery that only needs to be replaced every 10 years. “This can be done by field personnel in just a few minutes,” says Roughan.
“United Water became aware of our battery-operated mag meters,” he says. “When they began the zoning project in Westchester, they selected our meters.”
According to Curcio, the accuracy of any meter is dependent on the flow rate that is anticipated through that meter. Generally, the higher the velocity through any meter, the higher the accuracy.
“So, we needed to determine what the range of flows was going to be at each meter site,” he says. “For example, flows in overnight in January tend to be extremely low, as compared to peak usage hours in July and August.”
Once this was determined, United Water began having some discussions with Siemens related to the sizing of the specific meters at each site. “We provided them with flow information at the various sites, and they came back with some accuracy information for different flow ranges and meter sizes at each site,” says Curcio. “We then used our internal criteria to determine what the proper size would be for each meter–one that would fit the flow profile so we could achieve the accuracy we were looking for at that specific site.”
While the project has turned out successful, there were a couple of challenges along the way. “In implementing this project, we didn’t want to impact the capacity of our distribution system, and capacity can be impacted in a number of ways in this type of initiative,” he says.
The primary way capacity could be impacted is in what United Water calls “sectorizing” the boundaries, which is the process of ensuring that any flow that crosses between zone boundaries is captured by a meter. “You can’t have any flow crossing boundaries that is unmetered,” says Curcio. “However, it would not be feasible to put a meter at every boundary of every zone crossing.”
|Credit: MODERN ELECTRIC WATER CO.
Corrosion and improper threading can cause leakages.
So, at boundaries that were more critical, the utility elected to place a meter, but at boundaries that were not as critical, it elected to sever one of the boundaries between the two zones with a closed valve. “However, closing some of these boundaries had the potential to impact the flow capacity of the system, specifically our ability to provide fire flow capacity.”
The second capacity-related challenge was the potential to reduce meter size too much. “For example, if we have a 16-inch pipe crossing a boundary, we would be nervous to put a four-inch or six-inch meter on that, because that could create a bottleneck in that flow path,” he says. In order to make sure that the utility balanced meter accuracy with being able to retain the capacity of the system, it engaged in some hydraulic modeling work.
A second challenge was to make sure that the utility would be able to provide the water quality that customers needed. The age of the water, such as might be created in isolated pockets of old water, needed to be monitored. “So, when we examined the fire flow and capacities, we also examined the water quality,” says DiMenna.
Another focus for United Water was education. “Not only did we educate our internal staff on what we were doing and why we were doing it to make sure everyone was on board with it, but we also educated the municipalities and other customers that we were serving,” says DiMenna.
Given United Water’s commitment to comprehensive preparation for the project, it has achieved some meaningful impact in terms of identifying existing leakage and making progress in repairs. “In addition, by monitoring the production profile in each zone, we are also able to identify new leakage much faster,” says Curcio. That is, by having smaller zones, the utility is able to spend less time looking for losses, and more time finding and dealing with them.
“In addition, because we spent so much time educating our staff, they feel they have a greater part in it,” says DiMenna. “For example, the field staff are now more likely to report possible leaks, because they feel like they are actually making a difference.”
Modern Electric Water Company
“As a water utility, we are always looking for leaks,” says Bryan St. Clair, water superintendent for the Modern Electric Water Company (MEW) in Spokane, WA. And it is a never-ending opportunity and challenge. “Over the decades, the technology that is available to identify water leaks has gotten more refined. However, the need to conserve water continues to become greater.”
While all water utilities suffer from water losses, MEW has an additional challenge, the result of the type of soil in the region. “We have found leaks that are leaking 40 gallons a minute that never come to the surface,” he says. “The reason is that we have a lot of alluvial soil, rocks and sand, which sucks the water up like a sponge.”
The utility itself uses Geophones to identify as many of its own leaks as it can. However, according to St. Clair, the most important key to success in a leak detection program is to work with a good leak detection contractor that has the right equipment. MEW works with American Leak Detection (ALD). The utility has arranged for ALD to come out for one or two weeks a year, for two years in a row, to cover 100% of the utility’s system during that period of time. It then skips the third year, and has ALD come back the following year, for two years in a row, and so on.
“We arrange to put a crew guy with them when they are working,” says St. Clair. “And, depending on the road we are working on and the amount of traffic, we often end up needing to do some of the work at night.” ALD then provides the utility with a leak detection report, usually on the order of about 20 pages. “We then spend the spring and fall repairing the leaks they located,” he says. “We are busy doing other things in the summer.”
Besides the scheduled visits, the utility will have ALD come out at other times. “If our people are out and hear something and can’t readily find it, we will have American Leak Detection come out and find the leak for us,” he says.
What are the most common causes of leaks for MEW? There are several. Some of the most common sources, according to St. Clair, are fire hydrants that have been operated or closed improperly. A second cause is improper installation of water services, such as situations where pipes were bent or threaded incorrectly. A third is the
result of someone tunneling underneath a pipe, and the ground subsequently
settles on top of the pipe, causing downward pressure. A fourth involves contractors accidentally hitting a pipe. A lot of times, according to St. Clair, contractors don’t want to report it or admit it, because they are afraid they are going to be charged. “We explain to them that we won’t charge them, but that we need to know about breaks as soon as possible so we can repair them,” he says.
Partial funding for the leak detection program comes from a federal wholesale regional utility, Bonneville Power Administration. “One reason they are willing to fund these programs is that, when we are able to save water, it saves power, since we don’t need to pump as much water,” says St. Clair.
As a result of the utility’s aggressive and constant leak detection efforts, system losses are currently down to about 8.7%.
|Credit: UNITED WATER
Meter setup for one zone in a sectorization project.
|Credit: VIRGINIA RURAL WATER ASSOCIATION
Excavating to get at a leak
Tuckaleechee Utility District
When Lynn Valentine, general manager of the Tuckaleechee Utility District (TUD) in Townsend, TN, arrived at the utility five years ago, one of the first things he wanted to do was find where the non-revenue water was going. “The Board authorized us to hire Advanced Leak Detection, and their representative, Jeff Deel, walked our entire utility district system, which consists of about 170 miles of water lines, and reported back with several leaks that he found.”
“I completed the leak detection survey for Tuckaleechee in 2010,” says Deel, the owner of American Leak Detection of East Tennessee. “It took about three months.”
According to Deel, one reason he was hired was that Tennessee has become a lot more aggressive in trying to control water losses among the utilities. ALD follows the AWWA M36 Standard for leak survey and detection.
On the survey, Deel started out looking at every contact point on the line, any appurtenances above ground, and any contact with valves (while noting the locations of those valves), and took stock of any leak signals either to locate the leak at that time, or come back and locate it later. He then marked the location so that the utility could come back and do the repair. “I found between 65 and 70 leaks during that first survey,” he says.
One reason for the number of leaks was the combination of different material being used at the time. “They had a mix of different pipe materials–PVC, galvanized, copper, Blue Max polybutylene, polyethylene, and more,” says Deel.
“During the time I was doing the survey, Lynn was arranging to locate all of the meters and put them on a GPS, so they can look up on the computer and locate the valves and meters,” adds Deel.
This helped Deel in the process. In fact, one thing he recommends to utility clients who are interested in leak detection services as a way to improve efficiency and reduce costs is to be prepared. “They should know where water meters are located,” says Deel. “Some utilities actually can’t find some meters. If we miss even one meter, we miss checking it for a leak.”
Following Deel’s initial survey, TUD has installed a SCADA system so that it can monitor the equipment better. “SCADA lets me get on top of problems before they get out of control,” says Valentine. “SCADA not only helps us identify leak events, but has also helped us establish a baseline of where we should be.”
Valentine has subsequently zoned the system into four different zones. “We also installed zone meters, and we can review those meters remotely with SCADA,” he says. “All of that information is on a computer screen in front of me, and I can look at those numbers any time of day or night. Now we can look at the SCADA, and if we see something change in the system–such as pump run times–we will then start actively looking in that specific zone.”
In addition, besides using the services of ALD for the initial leak detection survey, TUD arranges for Deel to come out if and when the utility is aware of new leaks but can’t find them with its own leak detection devices. “His equipment is better than ours,” says Valentine.
“Since the first survey I did, Tuckaleechee has been looking for pressure differentials,” says Deel. “When they find a pressure loss, they call us back again to identify new leaks. In addition, they have called us back on several other locations to locate some leaks.”
What are the most common causes of leaks for TUD? “Several of these lines were installed in 1959, so they were quite old,” says Valentine. “Most of our leaks are caused by weather changes. Whenever it gets very hot or very cold, the ground will shift and cause leaks.” In addition, the system has a lot of PVC service lines, and these are the source of a lot of leaks. “We have been replacing these with copper, even though it is more expensive and not as easy to work with as PVC,” he says. “However, it is more effective in reducing leaks.”
As Valentine sees it, the most important key to success in water loss management is vigilance–staying on top of the problem. “You always have to be looking for leaks, and you can never let your guard down,” he says. Water loss has been reduced 20 to 25% since he arrived at the utility five years ago.
TUD is not finished, though. It is also in the process of installing automatic meter readers, and is currently about halfway done. “When this is completed, will be able to see what is going into each zone, by reading the zone meters and then comparing that to what we are actually selling, by reading the customer meters electronically,” he says. This, of course, will be another excellent way to identify water loss.
Virginia Rural Water Association
The Virginia Rural Water Association (VRWA) works with rural utilities in the state with populations of 10,000 and under and is funded through a Department of Agriculture program. The VRWA offers a number of services, including water loss programs.
“Besides conducting emergency leak detection services, we also go in and work with utilities on water accountability, especially if they are experiencing large water losses,” says Kenny Reynolds, training specialist, who spent several years in the field working with utilities on water loss issues. “Last year, we worked with 50 to 60 different utilities around the state on leak detection. On average, we will work with a utility for two to three days at a time.”
According to Reynolds, some utilities in the state lose less than 10% a month, which is considered good. “This should be a goal for all utilities,” he says. “An average loss rate is about 20%. Utilities should consider 30% or more to be a serious problem.”
At one utility, the VRWA team found three leaks in close proximity to each other that were leaking a total of about 600,000 gallons a day, without a drop of water showing anywhere on the surface. The most common cause of leaks is the result of older infrastructure–a lot of old pipe in the ground, and a lot of pipe that has had several repairs. Another common cause is ground shifting in the summer and winter.
Another source of water loss is meters that are not calibrated properly. “There are a lot of older meters that under-register,” says Reynolds. “Very few of them over-register.” There are also some instances of meters that are installed but not properly programmed into the billing system.
And even the failure to include a “zero” in the billing system can lead to millions of dollars of lost water revenue. For example, many larger meters read in the thousands, instead of the hundreds, so, for the billing system to accurately read them, there needs to be a multiplier of 10. If that multiplier is not added to the system, utilities will end up billing for only 10% of the water they are providing.
Reynolds is familiar with one such case. “Fifteen years ago, a utility left a zero off its system, and it was showing that a customer was using 200,000 to 900,000 gallons a month, and it was billing for that,” he says. “However, the customer was actually using between two million and nine million gallons a month.”
Town of Middleburg, VA
One satisfied user of VRWA services is the Town of Middleburg, VA, which learned that small systems can have big leaks. The town has about 700 people and 480 connections to its water and sewer system.
“When I became town administrator in November 2010, it became apparent during the budget cycle that followed shortly thereafter that the auditors had been noting, for years, a large percentage of unaccounted-for water, when they compared water that was billed with water that was produced,” says Martha Mason Semmes, town administrator. “They had been bringing this to the attention of the town for a number of years, but not much had been done.
I decided it was time to do something.”
After conducting some research, she realized that there were three possible causes: a problem with the billing system, really old meters that were not as accurate as they should be, or water leaks in the system. “I decided that we should attack all three,” she says.
She contacted the VRWA and received a visit from Reynolds in May 2011, who conducted a leak detection study of the town’s system. “He found a huge leak in a residential area on the west side of town that was so deep that it wasn’t showing up on the surface,” says Semmes. “The lines, which were two-inch galvanized lines, had been put down a long time ago. Since that time, someone had built over it. They went down 10 feet and still weren’t able to locate it. They finally located it at 12 feet deep and actually had to trench it.”
Fortunately for the town, a newer 6-inch line had been put in to serve the new houses, so all that was necessary was to abandon the old line and connect it to the new line.
“We estimated that it had been leaking about 1.2 million gallons per year,” she says. “To add insult to injury, there was a sewer manhole nearby. You could open the manhole, look down to the bottom, and see the water pouring into it.”
There is a pump station below where the sewer manhole is. After the leak was stopped, that pump station saw a reduction in pump station flows of over 500,000 gallons a year. In other words, almost half of the fresh water that was leaking from the 2-inch pipe was ending up in the sewer line, then being pumped to the wastewater treatment plant and being processed as wastewater! “So not only were we losing treated water, but we were paying to treat it again as wastewater,” she says.
The town arranged for a follow-up leak detection study in early 2013 and didn’t find any new leaks. “However, we intend to continue to avail ourselves of the VRWA’s leak detection services on a regular basis,” she says. “We are also planning to replace all of the old two-inch galvanized lines in the system to continue to help prevent future leaks.”
The town has also undertaken a meter replacement program, systematically replacing all of the meters with new meters that have touch-read capabilities, starting with the largest ones first.