George Kunkel, labeled by at least one industry insider as the “godfather of leak detection,” has overseen the City of Philadelphia’s leak detection surveys for the past 30 years. It may be the oldest leak detection program in the US, but, fitting for what is arguably the oldest water distribution system in the country, it is 200 years old.
Kunkel has also served on the American Water Works Association (AWWA) Water Loss Control Committee, which developed the Water Audit Software. This software allows utility users to calculate the dollar value of both apparent and real water losses.
The AWWA and Kunkel are trying to retire the term “unaccounted for” water and replace it with “non-revenue water” leakage. The reason lies with the definitions of apparent and real water loss. The former represents retail losses primarily from poorly calibrated meters, unauthorized consumption, and billing errors. Real water loss comes from leaks or overflows in the transmission and distribution system.
Kunkel says water utilities bury their pipes underground and suffer from the malady, “out-of-site, out-of-mind.” But all pipe systems are going to deteriorate over time and leaks will occur. Most utilities respond with “reactive leakage management”–wait until it breaks, and then fix it. In this case, the utility will miss out on hidden leaks, running site unseen and trickling away, he says. A number of them rupture and become disruptive to other infrastructure, like streets.
Proactive leak management is typified by the philosophy that, “If we could find and repair the leaks, we will minimize the big events,” says Kunkel.
Unfortunately, most utilities don’t do this–he estimates 90% of the utilities in the US are reactive. “And it’s unfortunate for the industry,” he states.
Kunkel says the majority of utilities are stubborn about change. However, they are paying to produce, treat, and deliver water, and when it leaks away, the utility pays for that non-revenue water. Once the leaks end, operating costs are reduced. Until the utility accounts for that wasted water, they don’t know how much it is costing them.
The Philadelphia Water Department’s acoustic leak detection surveys are conducted by up to five two-man crews every day, day and night, on a distribution network of 3,144 miles of water mains. Kunkel says the department spends over $1 million a year on the surveys. “We can’t get around the system once a year; we average once every three years,” he notes. “In reality, we visit high-leakage areas every year and low-leakage areas every five years.”
Year by year, Kunkel says the department is looking at $2.455 million in cost savings. That represents water that is not being treated and pumped a second time.
The most common technology is acoustic- or soundings-based that pinpoint specific leaks, says Kunkel. This involves using a listening device, often called a logger, which identifies a leak in a general location. Correlators, spaced at distances on either side of the general location of a leak, are then brought in to identify the location more precisely. Ground microphones with headphones attached may then be used to verify the exact location. Today, this data is usually transmitted via radio transmission to laptops or central station computers.
A handful of utilities, like El Paso Water Utilities, are installing permanent listening devices on valves and hydrants to produce around-the-clock information, which speeds up leak detection by years. The listening devices, or loggers, pick up sounds and transmit them wirelessly to a central station. If managers are awake at 2:00 or 3:00 a.m. when the city is relatively quiet, they can hear the leaks. However, staff usually retrieves the sound data during the workday and graphs them on a computer.
Kunkel has been involved in devising a new technique called flow management. In an article (cowritten with Reinhard Sturm for the February issue of Journal AWWA), he describes the method as testing a district metered area in combination with advanced pressure management. This is a “predict-and-prevent” approach to achieve and maintain low leakage levels in the area. The work was originally part of a research project on leakage management sponsored by the Water Research Foundation.
The district metered area is a hydraulically discrete part of the water distribution system supplied via inflow points equipped with flow meters. Valves on water mains are closed to form an enclosure fed by one or more supply mains, similar to a pipeline feeding an island. Flow metering in the district metered area does not pinpoint individual leaks, but it gives the capability of obtaining a quantity of the collective leakage occurring. Also, excessive water pressures can be reduced and optimized, helping to mitigate pressure transients. Surprisingly, Kunkel and his partners found that roughly half of the leakage volume comprised background leakage, reflecting poor infrastructure or service connection piping conditions, which cannot be handled by acoustic leak detection.
They concluded that a traditional leak detection and repair campaign could be expected to resolve no more than approximately half of the leakage. Further details of the project should best be read in the Journal AWWA.
El Paso Water Utilities out in Front
Danny Heredia, with WCS Company in El Paso, TX, spent 14 years with Fluid Conservation Services traveling throughout North America selling leak detection technologies to utilities. He understands water utilities’ resistance to leak detection programs. “I was giving them answers they didn’t want to hear about,” he says.
Why? Heredia says if utilities do have leaks, they won’t do anything for several reasons. They will have to look for leaks and then repair them. Then it will change things like jobs.
“Utilities are very conservative,” he says. “They don’t manage leakage.”
According to Heredia, following a pilot project in 2000, the El Paso Water Utilities became the first utility in the country to install a permanent, automatic, system that monitors the whole water distribution system at all times.
The El Paso Water Utilities (EPWU) has 2,400 miles of distribution pipe and produces 107 million gallons of water per day supplied by two aquifers most of the year and from the Rio Grande River, which flows by the city, seasonally. According to John Balliew, EPWU water systems division manager, the new leak detection system cost the city $3 million and will pay for itself in about six years.
The department’s pilot project was carried out in 2000, and in 2004 it purchased 5,000 loggers that operate on batteries. It hired WCS to install the loggers on valves, set up the Permalog3 leak detection program for the utility, and monitor the loggers. Another 5,000 loggers were purchased and installed the following year. Close to 100 leaks were identified in the first year, Heredia says, and in the following years the number detected dropped significantly.
Permalog is an advanced leak noise logger developed by Fluid Conservation Systems, headquartered in Milford, OH, and one of the Haima Water Management companies.
El Paso Water Utilities reports it has found 591 leaks in the years since loggers were first installed beginning in 2004. In the first two years of the program, it saved 725 million gallons of water–twice as much as the city golf course uses in one year, Balliew explains. With the information provided by the loggers system, “we’re able to make informed decisions,” he says. For example, is further assessment required? Does the utility want to replace the pipe now or wait 10 years?
The utility has been able to delay capital improvements based on the data provided by the program, and in one case, says Balliew, an aging pipeline that was judged to need complete replacement proved to have five defective joints that could be repaired at a relatively low cost.
The utility compared the results of the pilot project, when 100 loggers were installed, to its traditional method of having an operator use an amplifier and speaker to check the hydrants and valves for leaks. First, it saved time based on the system’s 24-hour-per-day operation. Balliew says it would take two employees 10 years to do what the new system did in two years. The largest leak found was losing 140 gallons per minute, 60 times more than a person typically uses to take a shower, Balliew says. The leak left no trace of its existence on the street surface.
Balliew sees leak detection as an essential part of a water conservation program that addresses the long-term need to be a good steward of water resources. El Paso began its water conservation program in 1991 and has reduced per capita water use from 200 gallons per day to 133 gallons per day in 2010. A water supplier also needs to make sure it is not wasting water through leaks, he says.
“You cannot expect your customers to find and fix all their leaks while the supplier is dumping several hundred gallons per minute into the ground through hidden leaks,” notes Balliew.
The experience derived from the leak detection program has changed the utility’s paradigm for viewing asset life based on a fixed number of years in service. Balliew says the new paradigm, which should be adopted by all utilities, is, “if you have a pipe that isn’t leaking and is structurally sound, you don’t have to replace it.” He says the utility has some pipes that are 100 years old and are in good condition, while other pipes just a few years old are experiencing unusual issues.
City Installs Permanent Detection System, Finds 49 Leaks
The average water system loses anywhere from 10% to 40% or even 50% of its water, according to Dennis Siegert, municipal utilities solutions manager for Johnson Controls. A deteriorating infrastructure accounts for much non-revenue water loss. In order to optimize capital upgrades, he argued, instead of replacing all old water pipes, use leak detection technology to identify leaks and replace only those pipes.
Tricia Kuse, director of marketing and strategy for energy solutions at Johnson controls, explains that when water is lost in a utility’s water system, it eventually finds its way into sewage systems and must be cleaned and pumped for a second time. This leads to lost revenue. Cities that have excellent and inexpensive ground or well water also benefit from a leak detection program, Kuse says. Their motivation is sustainability.
“We’ve seen utilities with extremely high losses but production costs are low. This is not motivating them to go after leaks and repair pipes,” says Siegert.
Siegert agrees with Kunkel that most water utilities are reactive. In the beginning, like 100 years ago, a plain old stick planted in the asphalt or ground was used to detect leaks in pipes. Acoustic listening devices slowly developed, but when water was cheap and the technology cumbersome, utilities were not motivated to search for water leaks.
Siegert says more and more states are mandating that utilities have water loss programs. Texas has a soft mandate that utilities are required to get their non-revenue water loss to 15%. “We offer services to utilities by providing free audits using AWWA’s audit software,” he says.
The audit information is plugged into AWWA’s audit tool–in effect, an excel spreadsheet. Based on the audit, “we discuss what the findings are” and explain that Johnson Controls can help them correct both apparent losses through inaccurate metering and real loss through leaks. The higher the production costs, the faster the payback, Siegert says.
Johnson Controls does not manufacture its own equipment. It provides services using technologies manufactured by other companies. And there are a variety of leak detection technologies available, which are constantly evolving. The striking evolution in technology is in batteries, says Siegert. This technology, “has increased fantastically in the last 10 years.”
The City of Kingsport, TN, contracted with Johnson Controls in 2008 to install an automated meter reading and permanent leak detection system. At the time, the city estimated it was losing more than 1.2 million gallons of water a year to leaks. In the following two years, it found 49 line leaks and breaks. After repairing the pipes and eliminating the leaks the city prevented more than 1,685 gallons per minute of treated water from being lost.
The cost savings are not going into the city’s general fund. Instead, they are funding Kingsport’s infrastructure improvements, thereby avoiding dipping into reserve funds, raising fees or issuing revenue bonds.
Surveys Prevent Future Disasters
American Leak Detection (ALD) specializes in complete leak detection surveys for whole systems and manufactures its own equipment, but does not sell it on a retail market. Jimmy Carter, senior director of corporate field services, says the company serves all kinds of customers from residential to municipal utilities, even military bases. “A water district will know it has [non-revenue] water loss” before hiring ALD, he says.
Carter adds, “We’ll work with one or two guys at a water district going through with listening devices at valves, air vacs, fire hydrants, and curb stops. This survey tool looks like a sausage dangling at the end of a cord. Leaks escaping from a pipe at high pressure create a low-frequency sound that will travel down the pipe. These sounds travel down metallic lines at a much greater distance than in non-metallic pipes.
“Metallic, caste iron, or ductile iron can transmit a leak 1,500 feet away,” says Carter. “Once the sound is heard, a leak correlator or ground microphone is used to find the specific location of the leak. Leak sounds are difficult to hear without experience and knowing what to look or listen for.”
Carter says there are a lot more correlators now in different price ranges, allowing inspections to be done differently and closer. If a leak correlator can’t pick up anything, it’s because the non-metallic pipe doesn’t transmit the leak noises very loudly. A ground microphone is used to pick up sounds in non-metallic pipes by placing it directly on the ground and listening through headphones, he explains.
Districts have become more proactive in using analogers–devices that can be placed in large water lines and tracked through laptops, like radio-controlled smart balls. They work like correlators but stay on 24 hours per day, says Carter. The newer units that can transmit data back to the office have come on the market in the last four to five years. Using the data, workers can go back with a correlator to identify the location more precisely.
“Most big water districts are doing this,” he says. “Rural utilities, however, don’t have the money, so they hire us.”
The Kittery Water District, in Kittery, ME, has cast iron water distribution pipes that are over 100 years old. According to Mike Rodgers, the district’s field supervisor, the average age of the pipes is 60 years. Since 1973, ductile iron pipes have been installed. The district serves part of the cities of York and Elliot and all of Kittery. Its water comes from a series of ponds and open reservoirs in Kittery and York, ME.
Rodgers says the district chose ALD following a solicitation for bids based on their methodology and price. ALD conducted its survey over one month in November and December, 2010, listening to every possible location over the 95 miles of pipes, hydrants, inline valves, and air vents.
The Water District was motivated because it had a series of main breaks in early 2010, which is not a pleasant time to repair lines Rodgers says. They had to tear up a whole street where the three were located.
Surprisingly, only a couple of minor leaks were found on the Water District’s lines during the survey, but six or seven sizable service line leaks on private property were identified. The fact that ALD found them meant they were sizable, Rodgers says. Customers were not happy and understandably so. The Water District gave them 30 days to make the repairs. “The risk of their waiting was lost revenue for us,” he says.
The minor leaks were under a “hot top” road and were minor enough that the Water District was not concerned they would cause road deterioration before they could be repaired when the weather warmed up. The Public Works Department did not want the road disturbed during the winter months, says Rodgers.
“Going forward, unless we see non-revenue water loss, we’ll do a survey every 10 years,” says Rodgers. He says the district knows how much water is pumped to its customers and how much it sells. The difference between the two numbers is wasted water.
Rodgers says that surveys to identify leaks is a worthwhile expense, and some people don’t appreciate the cost of chemicals used to clean the water, the wear and tear on the system, and cost of electricity for pumping. “It’s a wasted resource,” he adds.
The New Technologies
Sewerin USA is a subsidiary of an 80-year-old German company, Sewerin GmbH, and a distributor of Sewerin water leak and gas detection products. Jim Miller, is global marketing manager for leak detection projects at 3M, which signed a contract for exclusive distribution rights with Sewerin in April 2010.
Miller says Sewerin introduced its newest product, the correlator SeCorr300, in May 2010. It comes as a kit with two microphones, which are spaced some distance apart above a distribution pipe. Using a laptop, by calculating the time difference between the two sounds and factoring in the measured distance between the correlators, the material, and size of the pipe, the location of the leak can be identified.
“We suggest people verify the location with a ground microphone such as an Aqua Phone before digging up the street,” he says. “The SeCorr300 can cover large distances of pipe and can handle plastic pipe, which doesn’t conduct sound well. Since plastic pipe is becoming more popular with city utilities the SeCorr300 has a distinct advantage, says Miller.
Loggers, which are placed on valves or hydrants, have been around for about 10 years, but in different formats. Miller says loggers are the best way and the quickest to know if there is a potential problem. The first models didn’t have radio transmitters, and the data was retrieved manually.
Problems with the early models emerged. When placed on valves, water would erode the seal of the logger and get inside, destroying electronics before the batteries needed to be changed. Miller says Sewerin did away with the seal and installed the logger inside solid aluminum housing. Competitors developed their loggers with seals so they can replace the batteries.
Purchasing a full series of loggers to cover a distribution system can be expensive, so Sewerin has launched a lease-to-own product with payments spread out over time. This should make it easier for cities to fund an automated leak detection system, says Miller. The investment is usually paid for in less than one year.
Echologics Engineering Inc., a subsidiary of Mueller Water Products, is headquartered in Toronto, Canada. Marc Bracken, vice president and general manager, founded Echologics Engineering Inc. in 2003. The company has focused its research and development on improving the accuracy of acoustic water leak detection and pipe assessment technology.
The company’s LeakFinder RT is a Windows-based leak detection system with an enhanced correlator function that identifies and amplifies narrow-band leak noise in small pipes up to 18 inches. It was designed to work with plastic pipes, multiple leak situations, and in scenarios where leak sensors have to be closely spaced and in areas with high background noise.
Bracken says the other significant advance his company’s research and development team has produced is a system for pipe integrity testing. Using acoustic waves, this technology measures the remaining wall thickness of buried water transmission and distribution pipes in a non-destructive way and without taking pipes out of service.
Bracken says the technology induces noise by fibromechanical shaking that induces waves in the pipe. Variations in the speed of the waves indicate the thickness of the pipe walls. As waves become slower, it indicates the pipe has thinner walls. The information, sent by radio transmitters to a laptop can indicate the structural integrity and remaining life of the pipe, giving the utility the basis for a decision on replacement or repair.
For larger-diameter pipes, the company has created the Transmission Main Leak Detection technology. Bracken says it is a different version of the same correlator technology used on small-diameter pipes. Water microphones or hydrophones are attached to certain air valves, such as pito taps, fire hydrants, or other flow monitoring points. A pair of hydrophones can be located along a pipe up to 1 mile apart to detect leaks. A radio transmitter sends data to a receiver attached to a computer where it can be graphed.
As he plans for future growth now that Echologics is part of the Atlanta-based Mueller Group, Bracken is looking forward to integrating the company’s technology into a “smart grid,” making it a more permanent part of a utility’s water system.
Echologics won a $990,000 contract with the Sewerage and Water Board of New Orleans (SWBNO) for a one-year contract, renewable to two years, to oversee its water loss management and water pipe integrity assessment initiative. Bracken says New Orleans’ water distribution system was traumatized by Hurricane Katrina, and it’s never been quite the same since. He says various contractors used by SWBNO before Echologics signed on were not able to find leaks because of the city’s high water table.
Bracken says Echologics’ first task is to stop the bleeding of treated water. He estimates in the first three weeks of work his three-person onsite staff has found water leaks responsible for losing an estimated 358,000 gallons daily of treated water–that’s equivalent to filling a swimming pool every day. The initial survey work has been on small pipes in an area where SWBNO knows they have problems and they have already been prioritized for repair or replacement. He says the detection is very difficult because the high water table muffles the sounds of leaks.
The next step is to evaluate the structural integrity of the system, identify those pipes that consistently break down even after repairs, and determine if they need to be replaced, says Bracken. Distribution lines will be tackled first, and then the larger mains. He says this work will take most of the year.
“One of our mandates is to establish a leak detection program and train personnel,” explains Bracken. The company will also repair and maintain the big water meters in the larger district transmission system.
