Finding and fixing leaks in the delivery system has been a high priority since 2007 when the De Pere Water Utility began buying water instead of pumping it from its own wells.

De Pere, a city of 25,000 near Green Bay, Wisconsin, is a member of the Central Brown County Water Authority, along with six other municipalities. The authority buys water from Manitowoc Public Utilities, which draws its water from Lake Michigan about 40 miles away. De Pere still maintains and regularly tests four wells, but they are now the emergency backup system.

“Since our water is purchased at a substantial cost, it’s imperative that we do as much as we can to find any leaks and identify where we’re having any kind of water loss,” says Eric Zygarlicke, water department supervisor. “Water that’s not being billed through meters is something we have to absorb, and ultimately the ratepayers absorb that cost, too.”

The utility has done such a good job of leak detection that it won the 2023 Water Efficiency Award from the Wisconsin Section AWWA. Now the utility wants to take its water loss control to a new level. After working with a variety of contractors over the years, De Pere this year is buying its own acoustic leak detection equipment (Sewerin) and training staff to use it.

“We’re looking to get staff to do leak detection on at least half the city every year,” Zygarlicke says. “The hope is that when we get efficient at it, we’ll be able to do the entire city every year.”

PRIVATE SYSTEMS

Zygarlicke and Scott Thoresen, director of public works, have also targeted private systems supplied by the municipal utility. Those systems supply subdivisions or multi-unit buildings and have their own hydrants, valves, shutoffs and mains.

Without a mutual agreement, the city is not able to test the private systems, but an ordinance passed last January that would require the owners of those systems to work with the city or contractors to detect leaks and make sure their equipment and underground pipes are maintained properly.

Many older private systems don’t have a master meter, so water lost after it enters the system but before it reaches an individual customer meter is not billed to anyone. “We’re trying to find any water that might not be billed,” Zygarlicke says. “In our experience, those private systems are not maintaining a lot of their distribution system, and they are not really looking at their valves and hydrants or looking for leaks.”

TECHY TOOLS

Besides the leak detection equipment, De Pere uses technical tools both to monitor meters and bolster communication with customers. Smart meters and an advanced metering infrastructure system (Sensus - a Xylem brand) alert the utility if an unusual amount of water is passing through a meter.

“We are able to track usage and be alerted to obvious leaks after the meter,” Zygarlicke says. “We get a weekly report on any meters that might be experiencing abnormal usage or other things that might be going on in the system.

“That helps our customer base mitigate any kind of surprise bills. We bill quarterly here, not monthly. If you have a large leak going on for 90 days, that can be a substantial cost for the customer, so we monitor all the meters.”

De Pere also uses a web-based portal (AquaHawk) that allows the utility to analyze and monitor all meters for abnormal usage. The program is accessible to their customers and empowers them to monitor their own usage.

About 1,800 of the utility’s 9,365 customers (19%) are registered users of AquaHawk. “It’s very popular in areas where we have apartment complexes that are individually metered by unit,” Zygarlicke says. “Property managers love to use that as a tool.”

Zygarlicke has also trained on using the AWWA’s M36 auditing software for water loss control.

“It’s basically a souped-up spreadsheet where you can put a bunch of water system information in,” he says. “It does a little internal analysis and tries to point you in a direction where you might want to concentrate.”

He also takes part in a water efficiency group with his state AWWA section. The group meets regularly to discuss new and emerging technology and share best loss control practices.

MAIN REPLACEMENT

In recent years, De Pere has reduced the number of breaks in the city’s 126 miles of water mains. One reason is the installation of variable-flow drives on all pumps. “We have slow, soft starts now on all of our motors, including our wells, so we’re not creating any kind of water hammer that might cause leaks or main breaks,” Zygarlicke says.

Another factor is an aggressive program of replacing old water mains: “We’re getting rid of a lot of the cast iron mains and replacing them with PVC mains. It used to be nothing to have 25, 30 or 35 main breaks a year in the city. Now, we’re probably down to about a dozen to 15.”

Zygarlicke says it’s difficult to say whether customer-focused programs such as AquaHawk or the utility’s programs are more effective at stopping water loss. “They go kind of hand in hand,” he says. “AquaHawk deals with water loss on the customer side. It’s being billed, but they are paying for water that they are not actively using.

“Leak detection, on the other hand, deals with water that is not getting to the meter. It helps customers and the utility. If we’re not locating those leaks, all of the costs of that water get passed on to the ratepayer. Keeping costs down has been a major focus for us. It is imperative that we do our due diligence in finding these unbilled leaks in the system.”