Water loss can be attributed to unbilled authorized consumption such as firefighting or flushing water mains, unauthorized consumption, and real losses due to leakage. All are examples of non-revenue water loss.
Utilities can conduct system-wide water audits to assess leakage by estimating consumption and loss through the use of performance indicators, metrics, and benchmarks. Or, they can use technology to locate leaks. Most use sound to identify the location, although increasing use of smart technology can also help.
The key to success in maximizing savings and minimizing water loss depends on the early detection of leaks to reduce their duration, with the goal of repairing them before they progress to costly water main breaks.
It’s no secret that the country’s water infrastructure is aged and, in many cases, deteriorating. Leaky pipes can cause service disruption and can have a severe economic impact from the loss of treated water, increased maintenance budgets, interruptions, and property damage. Even before the situation deteriorates to the point of leaks, pipes can suffer from reduced flow capacity and pressure.
An essential factor used to quantify the condition of underground pipe is water main break rates, which are calculated for all pipe materials used to transport water in order to judge performance and durability, as well as to aid in asset management decision making.
Utah State University’s 2012 and 2018 water main breakage studies, which reviewed almost 13% of the total length of water mains in the US and Canada, reported that during that six-year period, water main breaks increased by 27% from 11 to 14 breaks per 100 miles per year, with smaller utilities experiencing break rates more than twice as high as larger utilities suffer. Significantly, the break rate of cast iron and asbestos cement pipe, which make up 41% of the installed water mains, have increased by more than 40% over a six-year period. (Folkman, Steven. “Water Main Break Rates In the USA and Canada: A Comprehensive Study” (2018). Mechanical and Aerospace Engineering Faculty Publications. Paper 174. www.digitalcommons.usu.edu/mae_facpub/174).
The survey, one of the largest conducted on water main failures, collected information from 308 utilities covering 197,866 miles of pipe. It recorded 23,803 failures that needed to be repaired. The report is used to update the average estimated service life predictions for pipe materials when considering asset management pipe repair and replacement decisions.
Pipe material differs by geographic region. The four most common types include cast iron (28%), ductile iron (28%), PVC (22%), and asbestos cement (13%). The remaining percentage consists of HDPE, steel, molecularly oriented PVC, concrete steel cylinder, and other materials.
The empirical data in the two Utah State studies compare changes over time regarding water main break data in order to benefit water asset management planning, but the American Water Works Association also conducts studies to formally track issues and trends. As long ago as the 1990s, the AWWA indicated that aging infrastructure was a concern and water main replacement was inadequate, an issue that remained a concern in their 2016 and 2017 surveys.
The Utah State study found that 16% of water mains are beyond their useful life, but utilities don’t have the funds to replace them. An Environmental Protection Agency study in 2002 indicates that the number of pipes in need of immediate replacement is growing, but only 0.8% of installed pipes are replaced annually. At the current replacement rate, the expected service life of pipe is 125 years; however, the average age of failing water mains is only 50 years.
In addition, state and provincial regulatory agencies across North America are bringing forward requirements for water utilities to report on current non-revenue water levels and take action on improving data reporting and lowering water losses. States such as California, Georgia, Texas, Tennessee, and the Canadian province of Quebec are among some of the leaders in regulating utilities to control system water losses to economic levels.
With more than 286 million Americans getting their water from a community water system, it is imperative to maintain water pipes and minimize water loss. The Utah State survey states, “It is believed that at many utilities, pipe replacement levels are inadequate to keep up with the rate of deterioration. Maintaining an obsolete system can cause severe financial hardship for cities as well as increase public health risks.” It suggests managing assets at an acceptable service level at the lowest life-cycle cost.
Based on the studies, it’s clear that the key strategy for maintaining a working water system is to locate and repair leaks, documenting the information for future analysis. “The last step is missing from many utilities,” says Kelly Olson, senior manager of business development, Core & Main, the largest national distributor of water, wastewater, storm, and fire protection products. She is a proponent of core asset management—the collection and repository of data such as GIS locations, as-builts, field inspections, repairs, conditions, performance, and monitoring.
Olson is also a proponent of using a mobile format in the field. “It’s important to get digital information…to collect data so you can do mapping and historical analysis.” She also advocates using GIS mapping to actively maintain assets and suggests using InfraMap, a software conducive to asset management. “You can use a tablet [in the field] to digitally record the location, the type of crack, the type of pipe, and what was done to fix the problem.” In addition, it can help predict future leaks.
Finding a leak underground is difficult, Olson explains, because no one knows where it is. The use of leak listening devices like those from SubSurface Instruments can aid in leak detection. They attach to the valve of the hydrant and listen to the pipes for clues like higher velocity, a whistle, or a loud rush. “You have to keep moving around the system to pinpoint the leak between valves. It’s very labor-intensive.”
However, when the amount of water being pumped doesn’t match the amount of water being billed, a leak is the possible culprit. If the water loss is more than 10%, it’s not getting to the customer, Olson says. At that point, “you need to find the leak and fix it. A listening device will help, and a leak listening system will document it correctly.”
Proper documentation is a critical step in asset management communication. “The younger generation speaks a different language, but as the older generation retires, they are taking knowledge with them,” observes Olson. “Documentation can be an important aspect of succession planning.”
The only downsides she notes are a technology buffer and the cost. Nevertheless, she sees a changing of the guard. “Digital leak listening is the way of the future.”
CAN YOU HEAR ME NOW?
A leak sensor on the pipe next to the community module that is connected to the meter listens to flow in order to find leaks. This acoustic system pinpoints leaks by listening to water volume, explains Mike Scarpelli, director of product management and customer quality North America, Itron Inc. “The more leak sensors you have, the more you can pinpoint a leak.” He says that other technology requires a lot of coordination to pinpoint leaks. “Our product is smarter because the solution is connected. Our system works with all connected devices.”
He considers leak sensors an important part of asset management for detecting apparent and real loss. With non-revenue water loss at 30% globally, the real-time reporting and real-time alarms are key to catching leaks early. “If you pinpoint it, trucks don’t have to hunt [for a leak],” explains Scarpelli. “That saves time and is a more efficient use of resources.”
It’s one of the innovative ways in which utilities and cities manage water, Scarpelli continues. Software and smart networks provide visibility and information to empower the customer to conserve water and use resources more wisely. Satellite imagery and traditional use of AMI can also uncover leaks, particularly if the leak is a continuous flow, like a running toilet.
Once the data is collected, the utility can act on it by prioritizing which leaks to go after. Baltimore Water, for example, has discovered 180 leaks a month, according to Scarpelli. The data allows them to rank their leaks by urgency and address as needed or as time permits. By arming itself with this information, a utility saves water, electricity, manpower, and time.
Itron recently launched a new meter. The Intelis water meter is part of the company’s end-to-end smart water solution: network, community, back office, meter, community module, and leak aerator. No moving parts means lifetime accuracy without hardware maintenance. Real-time alarms and flow data from the meter, coupled with an OpenWay Riva water module, alert utilities to leaks, theft, and backflow.
IT’S 3 A.M. DO YOU KNOW WHERE YOUR WATER IS?
The 3 a.m. hour is very important to detect leaks, says Aaron Beasley, vice president of sales, Water Signal LLC. “You have to break down usage per unit [in multi-family dwellings] and middle-of-the-night usage. If use is over 3 gallons at 3 a.m., there’s a problem.” Similarly, in an office building where there should be no usage at night, if you see usage, you have a leak somewhere.
It could be a running toilet or an icemaker line. Whatever it is, Beasley says it would show up on the data collected by their device, which is non-invasively attached to the meter to turn it into a smart meter with a water signal graph that allows the customer to see and quantify water usage.
The key in leak detection is benchmarking: tracking usage to record a history. The daily snapshot is an important aspect of data collection. Then an algorithm is applied to break down overall usage per unit average.
“Our solution is data collection,” says Beasley. “We monitor and look for anomalies. Then we send alerts by text or email.” Hourly alerts indicate a major event that needs attention immediately. Daily alerts—usually sent by email—are used for high-usage or abnormal days. “The building response is to find the leak and make decisions based on the data, not an assumption based on the water bill.”
He says multi-family dwellings can save an average of 14% annually by benchmarking, and he has seen commercial offices experience a 30–40% reduction, although he says the difficult aspect for them to get around is the cooling tower. In addition to those savings, he says the return on investment sometimes includes sewer credits from the city.
The intent is to be proactive. In addition to sending alerts based on established parameters, Water Signal grants clients access to a dashboard so they can look at the data. “Everyone can see, from the CEO and president on down,” indicates Beasley, adding that some school and university systems let their students see in order to engage them in water usage and conservation.
Some customers want more, Beasley says. Water Signal trains them to use the system and perform data analysis. Smart technology is intuitive, he believes.
Education is the future, he believes. “We are barely scratching the surface now. Energy is at the forefront with LED; gas and water are just starting to come to the forefront.” It’s an important change at a time when 50% of irrigation is run-off and just one Houston company uses 70,000 gallons a day. “Water has an end date; we must manage usage.” That’s why his company, while geared to detection, is focused on conservation. “We want to save the world, one thirsty property at a time.”
GO WITH THE FLOW
Saving the world through water conservation is a noble and vital objective, but the short-term goal for many utilities is reducing costs. “Private water companies are loss-conscious,” says Barry Spiegel, director of sales, municipal markets, McCrometer. “Every wasted drop is revenue they can’t charge for.”
Clean water is expensive—and it’s also expensive to uncover leaks. “You need equipment and manpower to dig,” continues Spiegel. But there was a time, he says, when “no one cared about water loss” and “a lot of rural communities didn’t even have meters.” Over the years, however, the cost of non-billable water loss grew. “Now, it’s rare to find a community not billing—at least at a flat rate.”
One way for utilities to achieve “significant savings, depending on the cost of water” is to incorporate flow meters. “Water treatment plants filter things out of the water,” explains Spiegel. “Valves control the flow.” A flow meter can indicate a potential leak by recording flow measurement.
McCrometer is not a leak detection company. Spiegel explains that the company is the “only large pipe manufacturer of flow meters that can talk to AMI.” Their device connects to the utility’s AMI system to record the flow. “Our meters hook up to automated meters.”
McCrometer offers a full profile insertion meters for large pipe—their specialty—that don’t require shutting off the water to install. “There’s no cutting. You just insert the meter and go,” indicates Spiegel.
They provide around-the-clock coverage and their alarms and controls help utilities find water loss, whether due to poor accounting, theft, or leaks. “We find the general area of the problem. It saves time by pinpointing areas.”
They are particularly useful in cases in which one town sells water to another town. A meter is placed at the interconnect to record the amount of water sent and billed. It’s also convenient in areas where there are no power lines because it’s battery-operated.
Spiegel believes that a combination of flow meters, sound detection, and other devices allows for the rapid deployment of people to find a leak.
NARROWING DOWN THE NOISE
American Leak Detection Inc., an international franchise company for residential, commercial, and municipality water management, uses a wide variety of tools to locate leaks. “Trimble has new technology to record sound files from the hydrant onto a cell phone,” says Jim Carter, senior director of corporate field services. “The water districts like it.”
The company also manufacturers a microphone and leak finder that produces a GPS recording on the logger location. “With sound information on a computer, it can be difficult to determine if it’s ambient and background noise or leak noise,” says Carter.
The way to determine the type of noise is to rely on experience and use a wide range of tools to help identify the size of the leak, low or high pressure on the line, soil type, and whether the pipe is wrapped, which can muffle noise. Sometimes pipes are wrapped in a 20 mil plastic sleeve that makes detection difficult. He relates an instance of water ballooning into the coating, preventing spray and noise. “It was hard to find the leak. Sound changes when a pipe is not metallic or is wrapped in a coating.”
Traffic, wind, and ambient noise also affect detection of leaks. So can soil content—sand and rock are especially tough. Other underground infrastructure can complicate leak detection. Buried steam lines, water lines, and high-voltage lines produce noise that causes interference. “You can pick up a 60-cycle electric hum that looks like a possible leak,” admits Carter.
Different sized leaks produce different sounds. GIS location, diameter, and type of pipe material also affect the sound. That’s why experience is so important. “You need knowledge of the equipment,” insists Carter, adding that it typically takes about five years to become proficient.
This is why water districts need to be proactive, Carter believes, by incorporating metering with leak indicators and adding more loggers. “Hydrant loggers allow you to see sound and pressure and provide better data.” He says the use of this technology reveals 15–200 small leaks per survey. Finding them early saves energy, treatment, wear on pumps, and money.
SEEING IS BELIEVING
Problems with drinking water systems are mainly associated with the age of their pipes, reiterates James Perry, vice president of business development for Utilis Corp, a data provider to water utilities that has developed a new way of detecting NRW leaks by analyzing images from satellites. “Most metal pipes last 75 years at the most; newer systems built with plastics last 25 years.” In both cases, these systems have surpassed their usable lives. Due to this infrastructure breakdown, leaks are occurring with greater frequency.
That means the response by utilities has been reactive. A quick assessment of management in cities worldwide indicates that most utilities react to anomalies in their water management systems, such as measuring a pressure drop via a district metered area or smart water management system or responding to a flood from a pipe that has already burst. This results in significant water loss and expense.
“More and more breaks are occurring, [but] the cost to replace these pipes is too prohibitive,” Perry observes. The two methods most commonly used by utilities for managing non-revenue water are smart water management systems and acoustic leak detection. According to Utilis, most water managers use these methods because they are currently the best solutions available on the market. However, they are time-consuming and expensive, delivering a very low ROI.
“The older methodologies of simply ‘listening for leaks’ is inefficient and takes years to survey an entire system of pipes. Newer technologies are a huge capital expenditure, work on only a limited portion of the system, and [are] very expensive to install and maintain. A better way must occur.”
He believes Utilis has found a better way. They use satellite remote sensing technology that sees the signature of drinking water underground. It covers a vast area of land in one image (1,300 square miles) and provides points of interest to utilities, who, in turn, use their field leak detection teams to pinpoint leaks, fix, and repair before the leaks surface. “This avoids the damage that occurs with surfaced leaks,” elaborates Perry.
This full-system survey is a digital approach to field leak detection that he considers a more efficient use of resources. “By finding more leaks per day, we are the lowest-cost-per-leak-found in the industry today.”
Utilis detects leaks in water supply systems by analyzing satellite images and presenting results as a data layer within a web-based application. The satellite’s sensor sends electromagnetic waves to Earth that penetrate the first few meters (depending on soil conditions) and then scatter. A portion of the waves are reflected back towards the satellite where an onboard sensor receives and measures the energy. Utilis translates this energy into a unique signature that is based on the interaction of the electromagnetic wavelength and the material it is hitting.
Utilis remotely senses under- and aboveground water leakage using a primary algorithm that detects treated water through the analysis of satellite imagery and filters out all other signals. A large area can be assessed all at once, within minutes, with the ability to triangulate a leak to a small region. Unlike other satellites that are limited by daylight or good weather, the Utilis system is based on microwave reflectometry. Microwaves travel through atmospheric interference such as clouds, dust particles, and aerosols. Therefore, they work in any light.
The process works by a microwave sensor onboard a satellite acquiring images and processing a corrected image. Treated water leaks are identified by use of the proprietary algorithm, which removes undesired “noise” such as reflections of buildings, vegetation, and other topographical features. Data is then presented graphically as a GIS data layer. Teams in the field receive information enabling them to locate, confirm, and repair the leaks.
The system can survey large areas all at once in a single screening, as opposed to taking years. Other benefits include ease of use in any GIS system, remote operation, no installation required, and consistent results. It doesn’t require equipment on the ground; it uses electro-acoustic techniques to mark the location of the leak.
From the most basic early non-amplified aquaphones and geophones to more modern electronic amplified acoustic listeners and ground microphones, acoustic leak detection has been conducted through labor-intensive surveys of the distribution systems, relying on human expertise. However, says Alain Lalonde, Echologics director of business development for Mueller Water Products, periodic surveys are no longer considered best practice due to the rising costs associated with water, aging infrastructure, the shrinking workforce, and increasing regulations. “Real water conservation and loss prevention require ongoing and sophisticated monitoring.”
Echologics uses acoustic technology to find and monitor leaks and assess the condition of water distribution pipelines without breaking ground, inserting tools in the water line, or disrupting service. Acoustic sensors are attached to existing contact points such as fire hydrants, valves, or directly on pipes. A sound wave is induced in the pipeline and a pair of acoustic sensors capture data, which is analyzed using their proprietary algorithms to identify leaks and assess the integrity of the lines.
Each of their products focuses on a different aspect: LeakFinder-ST accurately pinpoints leaks before they become detectable by conventional methods. EchoShore-TX provides continuous leak monitoring for large diameter water mains while EchoShore-DX provides continuous leak monitoring for smaller distribution mains. EchoShore-M provides mobile leak detection that can be easily operated by utility crews and ePulse provides condition assessment of both distribution and transmission mains while simultaneously searching for leaks.
By identifying leaks at or near their inceptions, the runtime can be reduced, lessening the labor and costs needed to repair them. Lalonde mentions a UK company that manages 35,000 kilometers of water distribution network, supplying water to 4.3 million customers and water recycling services to 5.5 million customers. “Our client was due to replace 402 kilometers of water mains to optimize financial returns for its pipeline replacement program; ePulse condition assessment was used to help determine if and when certain sections of pipe needed replacement. We found that a 198-meter section on the replacement plan was actually in good condition and did not need to be replaced. As this section ran under an environmental protection area, the complexity of the work and risk of negative environmental impact would have added to the cost. This led to a direct cost saving of over $150,000, along with the added benefits of reducing the environmental impact, carbon footprint, and disruption to local customers’ daily life.”
The company’s first project in Southeast Asia was installed in Malaysia to survey more than 3,000 kilometers of pipeline. Within the first 17 months of deployment, they identified and located 252 leaks and were able to save more than 25 million liters per day. The utility expanded its leak detection program to survey an additional 1,500 kilometers of trunk mains at an average rate of 40 kilometers per week, accurately pinpointing 120 leaks and saving a further 7.9 million liters per day. “That’s a savings of 32 million liters per day—enough water to supply an additional 152,000 residents every day,” calculates Lalonde.
He believes that the automation of data collection and reporting is a key component to developing smart cities. “Monitoring smart water infrastructure gives utilities the ability to not only identify leaking pipes before they cause issues, but also [to] create significant operational efficiencies through optimized capital investments.” Through early detection of leaks, utilities can better manage their water main assets and help avoid costly and potentially disastrous events such as a major pipe burst on a bridge or near a hospital or a school.
However, he also thinks that the adoption of new digital technologies has not been fast enough in the water industry, in part because of the non-competitive nature of the industry and an “out of sight, out of mind” mentality. Nevertheless, when it comes to acoustic leak detection, the results and savings are realized right away. “Utilities are able to stop the loss of NRW, better prioritize maintenance, and know precisely when pipes need replacing,” states Lalonde. “Any one of these alone can result in huge savings, which is why leak detection and monitoring is an affordable necessity.”
He views the market opportunities that lie ahead in fixed leak detection and pipe condition assessment as “already huge” and thinks they will increase in conjunction with aging infrastructure and population growth. “Utilities and water distribution companies are becoming more proactive because it’s cost-effective.” Knowing the condition of pipe systems and finding leaks to fix is vital for this approach.