In times of fiscal constraint, non-revenue water (NRW) is a major issue for water utilities. In view of reduced revenues from water conservation and rising costs for power and chemicals, utilities are placing high priority on locating the causes of NRW and developing strategic remedies.

Solving the problem — getting NRW down to the optimum level — has two main components: reducing outright water losses and making sure water distributed is metered and billed accurately and completely. Many water utilities tackle NRW issues on their own. For those looking for help with the process and technology, one alternative is Echologics Non-Revenue Water Services, formally offered for about the past 15 months.

NRW solutions often consist of water audits that help municipalities see where losses are occurring. NRW Services is a broader solution that includes detailed water audits, leak detection and non-invasive pipe condition assessment from Echologics, along with metering technology and other offerings from Mueller Systems, like Echologics a subsidiary of Mueller Water Products. The service includes development of a management strategy that helps ensure minimal NRW levels going forward.

Jim Fisher, manager of Non-Revenue Water Services for Echologics, and Matt Thomas, vice president of sales and marketing for Mueller Systems, talked about the offering in an interview with Water System Operator.

wso: How did this comprehensive offering come about?

Fisher: Echologics started as a research and development firm looking at leak detection and focusing on large-diameter and plastic pipes where other technologies had not been successful. In time we began discussing the whole issue of water distribution systems, water loss, water meters and NRW, and it started to grow from there.

In 2011, Mueller Water Products acquired Echologics, adding to its history of more than 100 years working in water distribution systems with water metering, valves and hydrants. The combined companies have unique offerings that help solve the problem of NRW.

wso: NRW is a long-standing issue. Why can't utilities and communities simply perform their own audits and develop their own strategies?

Fisher: Some cities can, and they do. However, the water utility workforces are aging, and a lot of the knowledge base is leaving through retirements. Further, because of revenue shortages, open positions are going unfilled. It comes down to a question of time.

Another issue is technology. When you add more water meters, and with the advent of automated meter reading (AMR) and advanced metering infrastructures (AMI), there's literally gigabytes of data being generated, and it takes certain expertise to analyze that data and make good decisions from the analysis.

wso: What is the first step in an NRW study for a community?

Fisher: The first thing to do is have discussions with different department heads across the city, because each one has valuable information that can help solve the problem of NRW. The next thing to do is go to the source — the treatment plant — and look at the meters. Have they been tested for accuracy? That is one of the most important things any city should do. We have the ability to test the accuracy of those meters.

Thomas: The accuracy of the larger customer meters is also important. Two-inch, 3-inch or larger commercial meters generally make up only about 1 percent of the total meter population within a water utility, but they may represent 50 percent of the revenue. They need to be updated, tested and maintained quite frequently.

wso: Typically, how much of a utility's NRW consists of leakage?

Fisher: Generally, once you get down to the nitty gritty of it, leakage can be up to 70 percent of the NRW figure.

wso: When it comes to leak detection, how do you decide where to deploy the technology?

Fisher: Many utilities have 30 or 40 years of leak history. They know the ages of the pipes and the types of pipes. They're looking at critical mains where if something lets go, you may put a hospital or a school out of service, or disrupt traffic. They know the sore spots in their distribution systems.

wso: What are the basic technologies used for leak detection?

Fisher: The first step is general sounding of hydrants, valves and select services with electronically amplified instruments to detect the presence of leak sounds. Second is an acoustic correlation system with advanced data analytics. There are really two types of technology. One is a remote system with transmitters, a receiver and sensors, and the other uses fixed correlating pods that you program and deploy across valves, services, hydrants and other components.

We use three types of sensors, depending on the type of pipe. Regular accelerometers are great for metallic pipes. There are low-frequency sensors for PVC pipe. And then there are hydrophones that actually come in contact with the water column — they're installed on a fire hydrant or a corporation stop. All these technologies are non-intrusive. The sensors have a very low noise floor, and they're backed by powerful algorithms in the leak detection software.

wso: How would you describe the condition assessment technology?

Fisher: The pipe wall condition assessment technology uses the same tools as the leak detection system. You don't have to shut the system down or insert anything into the live water system to determine how much thickness and how much strength is left in the pipe wall. You're actually doing condition assessment while you're doing leak detection. It's a proprietary assessment process backed by significant expertise and computing power.

wso: How does the metering side come into play in NRW service?

Thomas: We start with the treatment plant and make sure we know what's going into the distribution system. From there, we account for the amount that went through the customers' meters. The difference is the initial NRW. From there we deduct what's called authorized unmetered use — water used for hydrant flushing and other purposes that are necessary to the maintenance of the system.

wso: How do AMR and AMI contribute to NRW analysis?

Thomas: What we're doing with these technologies is bringing the metering data back on the network. We can read the meters hourly instead of monthly, and we can read them all at the same time, so we can now correlate that back to the water being pumped into the distribution system and truly get an accurate picture or analysis of what is NRW versus revenue water.

So every hour we can account for how much water went into not just the total distribution system but actually into different parts of the system. We can set up district metering areas (DMAs) where we put master meters in place, so now we can actually monitor subsets of the distribution lines.

Now we can read all the water meters at the same time we read the DMA meters, and we can see the individual area where the NRW is located. This brings AMR/AMI to another level, where we can analyze this data and provide information so that the leak detection side of our offering can then go find the leaks more accurately.

Fisher: With AMR/AMI, we can take all the data that's coming in, minute by minute, and create a benchmark — a minimum night rate. When everybody supposedly is asleep and nobody is using a lot of water, that minimum flow within a small geographic area is an indicator of whether there is leakage or not. Once you create that benchmark across a number of DMAs, you see the sore spots. It indicates where the utility can best manage its resources, time and money to fix and control water loss within their system.

wso: In summary, what is it that makes this NRW Service offering different?

Fisher: It's the total package of analytics, maintenance services, leak detection, condition assessment, and metering technologies that Mueller Water Products, Mueller Services and Echologics can bring to bear to solve NRW problems.