Editor’s note: This article first appeared in the September/October 2014 edition of Water Efficiency magazine.
According to EPA, public systems face numerous challenges, including aging infrastructure, increasing regulatory requirements, water quantity and water concerns, and inadequate resources. These challenges are amplified through changes in population and climate.
It is estimated that the US will need to spend upwards of $200 billion on water systems in the next two decades for transmission and distribution system upgrades. Of that amount, $97 billion is estimated for water loss control. Average water loss in systems is 16%, with up to 75% of that being recoverable.
When Utility Services Associates, a company that provides water leak detection, asset, and efficiency services began in the mid-1980s, many utilities approached maintenance with an “out of sight, out of mind” mentality, leading to delayed maintenance and underinvestment, notes Rob Meston, company president.
“We are paying for it now with water lines leaking at alarming rates and demand and droughts stripping and outpacing supply,” he says.
American Leak Detection points out that leak detection helps reduce non-revenue water (NRW), liability issues, repair costs, and avoids system contamination.
While leak detection is only one component of a complete water system asset management program, it is usually the most cost-effective and quickest way to recover lost water and reduce revenue losses, Meston points out.
“An active leak detection program also is one of the best ways to mitigate losses in other areas of the water system, such as lowering pumping and treating costs, reducing overtime hours due to emergency call-outs for leak repairs, and lowering liability claims by locating and repairing leaks before they become catastrophic events,” he adds.
Utility Services Associates uses multiple methods to collect and analyze water loss data for its clients. If a water audit is required, Utility Services Associates uses the free Water Audit Software developed by the American Water Works Association (AWWA) Water Loss Control Committee, which can be found at awwa.org. The company also recommends this software for clients doing their own audits. Many utilities have already completed a basic (or top-down) audit, Meston notes.
Over the last 10 to 15 years, many types of equipment, technologies, and procedures have emerged, with some being better than others, says Meston, adding that his company will choose the most appropriate approach from what’s out on the marketplace to effectively and accurately locate and pinpoint all detectable leaks in any water system.
“We also develop procedures specific to our clients’ individual system,” says Meston. “For example, the approach to survey PVC is much different than the procedures and methods used to survey for leaks on metallic and asbestos-cement systems. We will cater our equipment, procedure, and methods to meet each client’s specific needs in order to achieve the highest rate of return.”
On any given project, Utility Services Associates technicians will have available almost any type of equipment, including leak noise surveyors, leak noise correlators, acoustic ground microphones, pipe and cable locators, metal detectors, and fully equipped mobile leak detection units.
With no two systems being alike, a main leak in one water system on 8-inch cast iron may be completely different than an 8-inch main leak in another water system, he adds. “If we can’t find a leak with a correlator, we may use an acoustic ground microphone or a probe rod and leak noise amplifier,” says Meston, adding some leak detection equipment manufacturers have requested his company field-test their equipment.
Even with all of the technology, the most important factor in leak detection is the person conducting the study, Meston says. “Leak detection is an art which requires many hours of training and a great deal of hands-on experience,” he says. “The best technology is no good if it’s put into the hands of someone without the training and expertise to use it or to recognize that it’s not the correct application for a given situation.” One must “know how to truly assist the client—as opposed to finding the easy leaks—collect the payment, and leave.”
Mitigating leaks through audits and detection helps water utilities reduce system leakage to an “economic minimum,” and provides them with the tools to continue to keep losses at manageable levels and prioritize for line replacement based on historic leak results as well as other efficiency measures, says Meston.
“This is done either entirely by us, entirely by the utility, or sometimes in combination,” he says. Regardless, it’s a three-step process:
The water audit, a critical and often most important first step for any utility, says Meston. There are two audit formats: “top down,” touched on already, which is compiled using available data and records, even if the accuracy has not been validated, or “bottom up,” a more thorough investigation into loss components to describe the nature of the occurrence of loss and accurately quantify the loss volume and cost impact.Add Stormwater Weekly and Water Efficiency Weekly to your Newsletter Preferences and keep up with the latest articles on water: green infrastructure, smart meters, stormwater drainage and management, water quality monitoring and water treatment.
Intervention, which addresses the findings from the audit through implementation of controls to reduce or eliminate water losses. A leak detection program is one of the quickest ways to recover lost water and lost revenue, Meston says.
Evaluation, which uses performance indicators to verify the successes of the chosen intervention actions.
Meston says many utilities are aware that leaks are a significant part of their system losses and will first get their
system, or a portion of it, surveyed for leaks so they can make immediate repairs and build a program from there.
With respect to audits, one of the first factors water utilities should consider is the NRW Management Strategy, Meston says. “A daunting task facing nearly all water utilities is managing and reducing NRW,” he says. “NRW is the difference between system input volume and billed authorized consumption. It is important that utilities implement a NRW Management Strategy with set operational and target performance indicators for NRW.”
By completing a “top down” water balance audit, a utility will not only identify the major components of loss and consumption, but costs are factored in which allow the utility to assess the financial impact of each component, enabling the utility to create an effective NRW management strategy, Meston points out.
Scott Wicklund, Utility Services Associates’s director of new technologies and training, says IWA/AWWA best practice methodologies are effective as they define water consumption and water loss in water systems.
“The IWA Water Balance Audit quickly identifies key performance indicators which allows utilities to assess their water loss, benchmark themselves against other utilities, and set performance goals,” says Wicklund. “The concept is that all water is quantified by measurement or estimate. This is a valuable starting point in any water loss management program as it reveals information that aids in the overall NRW plan development.”
In addition to displaying the system input volume and authorized consumption, the water balance breaks down water losses into apparent losses and real losses. “The water balance will assist the utility in determining several different types of performance indicators,” says Wicklund. “Operational efficiency performance indicators, financial performance indicators and Infrastructure Leakage Index [ILI] are all defined when the water balance is completed. The water balance will assist the utility in prioritizing areas in need of attention.”
When adopting a “top-down” approach, a grading matrix has been developed over 15 years that enables the utility personnel to base some of the data on estimates, says Wicklund. “The grading matrix reveals a weighted scale for the components that is included in the calculation of the data validation score,” he says. “Identification of key performance indicators ensures that the utility can develop its NRW Management Plan and reduce its loss in the most efficient way.”
Example in Arkansas
The city of Hot Springs, AR, has strategically and aggressively implemented an effective NRW loss control plan, says Wicklund. “Through diligent line replacement and active water leak detection projects, they have realized substantial water loss reduction over the past four years,” he says. “The plan includes hiring Utility Services Associates every other year to complete water leak detection surveys over strategically selected areas of the system.”
Phase I, conducted in 2010 and 2011, encompassed the entire district. Phase II consisted of city and consultant personnel defining the areas where the greatest return on investment in terms of reduction of water loss would be, based on numerous factors.
The system was experiencing an NRW real and apparent loss of 40%, or nearly 6.5 million gallons per day prior to the initial leak detection survey, says Wicklund, adding that the annual cost of NRW loss was about $1.7 million. The annual loss was about 2.3 billion gallons a year.
The city had recently installed an automatic meter reading (AMR) system.
During the first phase, some 852 miles of pipe were surveyed over a 148-day time period with 74 days spent pinpointing. The pipe included ductile iron, cast iron, asbestos-cement, steel, and 50% PVC/heavy saturation of two-inch galvanized steel. The system pressure was 80 to 120 PSI. There were 400 leaks pinpointed on the city’s side of the meter, with 54 identified on the customer side.
During the leak detection project, some 26,289 appurtenances were sounded. Some 43% in real loss reductions were realized, with many lines scheduled for replacement based on survey results; GPM was not estimated.
Hot Springs entered into an active replacement program in which several two-inch galvanized steel lines were scheduled for replacement as part of project to assist in prioritizing replacements.
The annual financial benefit of reduced NRW, not including repair costs, totaled $762,601. The estimated payback time for consulting costs was 3.3 months, the estimated payback time for the project, including 177 excavations, was seven months. The estimated first year financial benefit after all repairs were made is $312,251.
The 100-day Phase II leak detection survey was completed in 2012/13, notes Wicklund. It resulted in the pinpointing of an additional 167 water leaks that were either new, or had been masked by louder leaks during the initial survey.
“The results of Phase II continued to help identify and prioritize the water lines added to the replacement program,” he adds.
Metering Flows in Systems
Greg Webster, sales manager for McCrometer’s municipal water and wastewater market, notes in the past several years a “rapidly growing interest in capturing water losses and monitoring and improving efficiencies in water distribution systems across the country.
“Water is a precious commodity,” he points out. “There are drought conditions that have existed in pockets for the last several years that put stress on a system. Some of these distribution systems throughout our country are very, very old, and it becomes a challenge to figure out what’s going on.” Some aging systems may not have had any other upgrades other than additional pipe lengths added on to the system at some point through growth in infrastructure, Webster adds.
He references one operation that wanted to use the FPI Insertion Mag to improve efficiencies and offer more visibility with respect to their system. In the preliminary review, he spoke with the utility leaders regarding what type of pipe may be in the system.
“One guy looked at another guy during the meeting and said, “˜I think there might be wood out there because of the location.’ They weren’t kidding around. We were going to have to excavate around that pipe to find out if that’s what it was. At the end of the day, all of the locations were indeed ductile iron. But it was old, dating back to the 1940s.”
It’s guesswork for municipalities to determine why there may be water losses in a system until they use tools to pinpoint the nature of the problem. To that end, McCrometer offers the FPI Mag Flow Meter, an Insertion Mag Meter that uses hot tap installation, enabling the meter to be inserted without cutting pipe, welding flanges, dewatering lines, or interrupting service. The water flow sensor supports municipal water and wastewater applications.
The sensor body is manufactured from heavy-duty 316 stainless steel, is hermetically sealed, and protected by NSF-certified 3M fusion-bonded epoxy coating. The FPI Mag is available with forward-flow only or bidirectional measurement for line sizes ranging from 4 to 138 inches.
Water applications include distribution, effluent, UV dosing, filter balancing and backwash, and wells and booster stations. Wastewater applications include effluent, recycle and reclaim and industrial facilities, such as power plants including cogeneration, paper mills, chemical and petrochemical plants, metals and mining, and food and beverage. Other applications include cooling water, fire water, feed water, raw water, and inlet to surge basin.
Webster says a magnetic flow meter is the most widely used flow-measuring device globally because of its accuracy and reliability.
“They can be in service for a long period of time,” he points out. “There are no moving parts. They work on a principle referred to as Faraday’s Law, which says when a conductor moves through a magnetic field, it induces a voltage. Therefore, mag meters have taken over as the primary flow metering devices across many applications, particularly in the water market.”
Some municipalities, when suspecting leaks in an aging infrastructure, have had an employee walk the pipeline to try to detect where the main break is taking place, Webster says. At that point, a magnetic flow meter becomes attractive, he adds.
A municipality can split an entire distribution system into different zones and install the flow meters to capture accurate data across the entire distribution system, he says. Telemetry can be used to capture the information, sending it to a central location. Such information can be utilized for reporting purposes. It can also offer an instant view of where there may be a rapid increase in flow, enabling a quick response to improve operational efficiency.
Webster points out that many water operations don’t do much with respect to audits or leak detection because they are unaware of what’s available or may choose a methodology that’s less accurate than other options. “In that sense, they are throwing good money at a bad situation,” he says. Flow meters are one of the top tools at a utility’s disposal required to operate a system, Webster says.
“I think it’s moving up the chain because people want to know more,” he adds. “There was a time when water flowed and we really didn’t care too much about where it went. Everybody turns on their tap and expects water to flow. Some people think it’s free or it should be free and don’t really understand there are costs involved in the municipal distribution system and it has to be maintained.”
Aclara’s STAR ZoneScan system combines leak-detection technology from Gutermann International and two-way fixed network AMI technology from Aclara. ZoneScan, in concert with analytics, helps utilities determine non-revenue water, meter inaccuracy and leakage.
Aclara has created an MTU (the Aclara STAR Network Water Meter Transmission Unit) that will communicate with the sensor, which is attached to valves in the distribution system via the integrated magnetic base, and the deployed leak intelligence units monitor and analyze noise characteristics and detect and identify a leak’s location.
The MTU is set in place with a lid and “listens” to the system between 1 a.m. and 3 a.m. local time for signatures that a leak in the water system will make, says Steve Bruskiewicz, Aclara’s product manager for water.
“It will listen to that sound, and after it does a two-hour amplitude study, the system will correlate the distance between the two nearest sensors that picked up that leak and pinpoint the leak within three feet,” he says.
“After 10 a.m. on the following day, this data is reported to the utility through a dashboard, and they’ll be able to monitor their system anywhere the ZoneScan unit is installed and keep an eye on it for leaks. This gives the utility an opportunity to classify the leaks and repair the leaks on their own schedule.” The advantage of the system is that it picks up the leaks when they are small, Bruskiewicz points out.
“We and the AWWA have found that about 80% of the water that leaks out of our distribution systems never rises to the surface,” points out Bruskiewicz.
“These are all of the small leaks that end up following the water main and most of them end up getting into the sanitary sewer system and creating problems for the treatment plant,” he adds. “The goal of this product is for us to locate that 80% of the leakage, and give the utility the opportunity to schedule and repair the leaks in the most efficient and economical way possible.”
The STAR ZoneScan system automates the collection, retrieval, and analysis of acoustic data, leveraging Aclara’s STAR Network AMI system, including two-way communication between the utility head-end and endpoints, time-synchronized initiation of sound recordings, and an interface to Gutermann’s Web-based data correlation software. The system enables operators to select study parameters and analyze results at the utility office.
Utilities can compare total water consumption to water production to obtain a gross estimate of system water loss. In response to ZoneScan units deployed in targeted areas of the pipeline, repair crews can be dispatched to identified leak locations.
More utilities are moving to an AMI system, notes Bruskiewicz. “Where before they may have had a reading every three months or once a month, now they’re getting readings every hour,” he says. “Through data analytics and the STAR network, we have come up with methods to help the utility complete their AWWA water audit with the data they’re already receiving today.
“With the STAR system, you can get your billed metered consumption, billed unmetered consumption and your unbilled unmetered water, which are all of the authorized consumption values. It can populate all of those buckets with the data.”
The system also can pick up on apparent and real water loss. “It can calculate where the water is going, such as meter inaccuracy, and look at meter trending, indicating where water meters are starting to age,” says Bruskiewicz.
The system also can calculate that the proper meter is in the proper application, he adds. “You can have a two-inch turbine meter and a two-inch compound meter. The two-inch turbine meter is a much less costly water meter than the compound, but it’s good for reading high water usage, not low water uses,” says Bruskiewicz. “It’s not good at picking up when you turn on a faucet or flush the toilet, whereas the compound meters are designed to pick up those low flows, and through the data, the STAR system can indicate you’ve got the proper meter in the proper location.”
Bruskiewicz had operated utilities for more than 20 years, and as such, has worked on both sides of the fence and is cognizant that there are financial issues to consider against the backdrop of an aging infrastructure. “Money is very scarce for utilities, so they really need to quantify and qualify where they’re going to put their dollars,” he says. “Utilities know their bad areas. Every utility has parts of their system that are in pretty good shape, parts that are middle of the road and parts that are failing.”
While it’s optimal to install technology such as ZoneScan throughout an entire distribution system, when money is a factor, utilities can take a “life and shift” deployment approach, Bruskiewicz says.
Aclara recommends the product be placed in the areas with the most known problems to locate the leaks and make the repairs. “After you’ve gotten to the point where you’ve found all of your leaks and you’ve got all of your leaks repaired that you’ve found, then you keep the product in place for another month to monitor,” says Bruskiewicz. “If everything is good, then you can pick the product up and move it somewhere else. In that way, it gives utilities a way to control their dollars. It’s not like they have to go all in for the system because most utilities can’t afford that.”
One cannot underestimate the importance of an audit as part of an overall approach toward fixing water distribution problems, Bruskiewicz says. “It’s amazing when a utility looks at the result of a water audit,” he says. “I’ve seen audits where there is 50% non-revenue water—that’s 50% of the water that we as a utility are putting out into the system we’re not getting paid for. That happens more than you would think. Based on my experience, the average is probably 20 to 35% non-revenue water.
“There’s a financial piece to it which would tell you the dollar value of what you’re losing on an annual basis,” says Bruskiewicz. “Now you can calculate your return. I look at my water loss; I look at my water meters; I’ve done the water audit. I’ve got a pretty good idea of where I’m losing water. If I aggressively attack this, I can save “˜X’ amount of dollars annually. If I invest “˜X’ dollars this year, I am going to recoup those dollars in five to 10 years down the road.”
“When we look at leakage for water utilities, typically we’re looking at leakage that’s on the residential side of the meter or the distribution side of the meter,” notes John Parks, director for new business development for Neptune Technology Group.
For detecting leaks on the residential side, Neptune offers solid-state encoder technology called E-Coder. The technology divides a 24-hour period into 96 15-minute intervals, detecting flow in those 15-minute periods, Parks says.
“If there’s flow in all 96 15-minute intervals, it’s a very accurate indication that there’s a continuous leak on the residential side of the meter,” he says. “The E-Coder provides a leak flag. It can determine if there’s a continuous or intermittent leak in the house. An intermittent leak can be classified as a faulty flapper valve in the toilet or a sink that doesn’t tighten up enough and continues to leak.”
E-Coder identifies the leak types and reports them through the protocol back to the host software each time a meter is read, enabling a utility to determine the next step based on the information provided.
Some utilities bring the leak data into their Customer Information System (CIS) software, using it to report the leak states back to the customers, Parks says, adding that this is critical in states facing water supply shortages and needing to conserve water.
In addition to its basic E-Coder that can be connected to a stand-alone radio, Neptune also offers the E-Coder)R900i, which has an integrated R900 radio frequency meter interface unit (MIU) and provides 96 days of hourly data logging.
To identify leaks in distribution mains, Neptune has partnered with two acoustic leak sensor companies—Fluid
Conservation Systems’ Permalog and Vivax-Metrotech’s Leak Spy—that work with its AMR/AMI (Advanced Metering Infrastructure) systems.
“These devices listen for the sounds of leaks on distribution lines. Depending on the size of leak and the amount of water escaping the pipe, there’s a certain high-pitched tone that occurs. Based on the sound that they’re hearing, they can determine approximately where the leak is and how big it is,” points out Parks. “We work with (the acoustic leak companies) to output protocol that our radios can read and interpret.
“This information comes back into our host software where it can be reviewed to help utilities identify where they have leakage problems on the distribution mains and where they need to go in and pinpoint them more accurately.” Identifying leaks across the system—and their severity level—supports the auditing process, says Parks.
“Our R450 Fixed Network AMI system is designed to read every residential meter, every commercial meter, and every distribution meter at exactly the same time, at midnight every night,” he says.
That allows utilities to take a snapshot in time so they can measure the amount of water that they pumped through their distribution meters to the amount of water that was used through their commercial and residential meters. “By doing this, they can determine where along their distribution lines they have leakage problems,” says Parks.
At a micro-level–district metering–the utility can look at a district meter that feeds two or three subdivisions of residential homes and look at the amount of water that flows through the distribution meter versus the amount of water that was used through all of the residential meters.
“When they subtract the amount of water used through those residential meters from the distribution meter, if it’s right in the same line and the same amount, they’re OK,” says Parks. “If they’re missing a lot of water, there’s most likely either a leak somewhere between their distribution meter and all of those residential meters or their residential meters are not operating at new meter accuracy. Our AMI system helps them audit the districts within their system where they may potentially have leakage problems.”
Whether to invest now when money can still be tight for utilities against the potential for encountering more expensive problems down the road is the “age-old” problem, Parks points out.
“The water meters at the end of the day are the utility’s cash register,” he says. “If a utility’s water meters are not accurate, then two things are happening: they are losing revenue and could be losing water to leakage.” With so many areas facing water supply shortages and drought challenges, accurate metering is a significant factor in managing their water resource, Parks adds.
“Investment in accurate meters/new meters and investment in AMR/AMI technology can allow utilities to effectively monitor not only their meters but their infrastructure to identify where leaks are occurring, which is critical,” he says. “If customers are told they have a leak at their residence that they need to fix, and if leaks on distribution lines can be caught early, they can be repaired and addressed” before they get out of hand.
Itron’s approach to leak detection ties acoustic leak detection with its AMR/AMI system. The company has a leak sensor module on its ChoiceConnect 100-W system.
“We deploy that throughout the entire system so we’re constantly monitoring 24/7, listening for leaks,” says Mark Patience, the senior product manager for water communication modules and non-revenue water solutions for Itron.
“We also have other more complex correlating and listening devices that we use later on down the road once one of our sensor alarms pinpoints where a leak is in the system,” he adds. “We do a little bit of both, but our main approach is to deploy affordable leak sensors with our AMR/AMI system throughout the entire distribution system to monitor around the clock.”
Utilities can typically find water loss through audits as a result of water theft or utilities not metering public buildings or parks, Patience says.
“What we’re really trying to focus on with the acoustic leak sensor is the real loss, the actual leaks within the system,” he adds. “If they do an AWWA water audit, they’ll be able to tell how much of their water loss is apparent loss, which is your meter inaccuracies and so forth, and then how much is real loss–the actual physical water leaving the distribution system before it gets to the customer.”
The primary benefit of acoustic leak detection is its low cost compared to other technologies, Patience says. “This constantly monitors the system around the clock–you’re not surveying a section of pipe one day and moving into the next section, and then it might take you several years to get back to the section you just surveyed,” he says. “Who’s to say that a leak doesn’t occur the day after you leave–it could be six or seven years before you ever find it.”
Additionally, ongoing acoustic leak detection means locating leaks before they become major catastrophic issues, Patience says.
“It’s a lot cheaper to repair a five-gallon-per-minute leak in a small area than it is to repair that leak once it becomes a main break and you get to dig up hundreds of yards worth of road or you might have property damage or chemicals in the water,” he says. “Main breaks are a lot more expensive than repairing smaller leaks. If you’re proactive and you find the leaks before they become huge problems, it saves a lot of money just in repairs.”
The seriousness of water leaks depends on where in the US one resides, Patience says. With the exception of arid areas, such as the Southwest, “we have a lot of water here, so it’s not that anybody here is doing without water in the US,” he says. “It’s more the costs of energy to pump the water. If you’re pumping water that’s not being used, you have additional energy costs. You may have to expand treatment facilities. So the cost is getting higher.”
Patience points out that in other countries, there are places in which water users have access to water only a few hours out of the day. “We don’t have anything unusual like that here,” he says. “It’s more of a dollar issue: energy costs, repair costs, infrastructure costs.”
While the nation’s water utilities work to mitigate the problems of an aging infrastructure, the industry is also working to get ahead of the curve for future needs. Case in point: Envision for Sustainable Water Infrastructure, the product of a joint collaboration between the Zofnass Program for Sustainable Infrastructure at the Harvard University Graduate School of Design and the Institute for Sustainable Infrastructure.
A workshop introducing Envision occurred at the June annual conference of the AWWA in Boston.
Envision sustainable infrastructure rating systems encompass a new system of tools for promoting the water industry shift toward more sustainable development that includes criteria, a rating process, and the advantages and challenges in using the tool on water utility projects.
As such, Envision assists those using it as a tool to ascertain whether a specific project will help meet sustainability goals. “It’s also a powerful planning and design tool,” points out Bill Bertera, president and CEO of the Institute for Sustainable Infrastructure. “It is best used when introduced at the earliest stages of that project’s inception. It’s not prescriptive. It is based on established best practices.”
Envision serves as a checklist for engineers and others as they put together projects to assure that they don’t miss anything in the context of sustainability in that project, says Bertera. It’s a tool specific to issues of sustainability and doesn’t take the place of other tools, he adds.
“It is very flexible in that it takes into account the triple bottom line, which includes not just issues of engineering and decision-making, but also environmental protection, community values, priorities and the like,” he says.
After an audit, a water utility can move on to the next step of leak detection to help set priorities. Perhaps a section of the pipe needs mitigation or replacement, or maybe growing development needs require new infrastructure.
“That’s exactly the point where you would want to introduce this,” says Bertera. “You want to introduce it not just to make your project better engineered, but to make sure that the project you are pursuing meets all of the criteria of sustainability as well.” Sustainability doesn’t solely mean making something last longer, he says.
“We’re talking about the way we think about the future and the way we think about options not only for present needs, but for future needs as well,” adds Bertera. “The Envision tool helps designers, planners, and others think about that as they’re putting together their projects. We like to say this isn’t just about doing the project right, but doing the right project in the first place.”
While utilities conduct water audits on a large scale, when customers audit their own indoor and outdoor water use, greater water efficiencies are derived. According to the Natural Resources Defense Council, such audits are sometimes conducted at no cost by a utility or through performance contractors, who will finance water efficiency improvements in exchange for a share of the cost savings.
Case in point: The Port Authority of New York and New Jersey had upgraded restroom facilities at LaGuardia Airport to increase the efficiency of toilets, faucets, and showers. The port installed a leak detection system, ultra low-flow toilets, high-efficiency aerators for faucets, and flow restrictors on showerheads, which yielded annual water savings of almost $160,000 after an initial $90,000 capital outlay.