Each year, more than 2 billion gallons — or 12 percent — of Arlington’s treated drinking water is wasted before it arrives at homes and businesses.
Some is lost when water mains break because of weather changes, shifting ground or construction mistakes. Those problems are easy to spot, because water bubbles to the surface of the street. But it can be harder to detect smaller leaks in the miles of underground water lines and thousands of valves hidden beneath Arlington’s roadways.
After years of encouraging residential and commercial customers to use water wisely, Arlington is turning to infrastructure improvements designed to cut waste. Reducing the amount of water lost before it reaches customers by just 1 percent would save the city $300,000 each year, Water Utilities Director Buzz Pishkur said. That means lower costs to be passed on to customers.
“Because we will reduce the number of outages and the duration of these outings, our costs will be reduced through more timely repairs and reduction of emergency situations. Quite frankly, I believe this is what our customers pay us to do,” Pishkur said. “We are focusing on doing more for our customers, not to our customers.”
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This year, the Water Utilities Department launched several initiatives aimed at reducing water waste and keeping the system strong. Plans include replacing aging and brittle concrete water lines, manually inspecting thousands of water main valves and using technology, including a robot equipped with a high-resolution camera and special sensors, to detect leaks and flaws in pipe that can’t be seen from above ground.
Help from a robot
Earlier this month, a contracted crew from Pure Technologies deployed a robotic crawler to inspect the inside of a 24-inch water main running beneath Stadium Drive between Division and Abram streets. The city, which will soon widen Stadium Drive near the railroad tracks, wants to determine whether the entire section of the 30-year-old water main should be replaced at an estimated $1 million or spot repairs could be made for less.
The remote-controlled robot crawled along at 40 feet per minute, beaming back high-definition images of the mortar coating inside the pipe and data from electromagnetic sensors that detected weakness or disrepair in the steel bars that wrap the main.
“If we can show based on inspections there is nothing wrong with the line, that is a big savings in cost,” Dean Yanagi, a Water Utilities civil engineer.
It was only the second time Arlington had used the technology for an inspection, which cost the city about $169,000 for Stadium Drive. Previously, the city determined whether to replace a main based on its age and maintenance history, Yanagi said.
Problems with concrete
About 42 percent of Arlington’s water system is concrete pipe, like the Stadium Drive section, Pishkur said.
“Concrete pipe is our worst problem. It’s brittle and we have a lot of ground movement,” Pishkur said.
The worst sections will be replaced with more flexible plastic or metal pipe. Water Utilities plans to replace about 1,200 feet of water mains and 6,000 feet of sewer lines each year, which Pishkur said would help reduce wasted water.
Valves are another focus. Three two-man crews are locating and inspecting all 18,000 water main valves across the city, a project expected to take three years, Pishkur said.
“If you can’t find the valve or you can’t operate the one you find, then you have to go to the next one or the next one,” Pishkur said. “If you don’t exercise them, they seize up. They are like any mechanical piece of equipment.”
Knowing where all valves are located and making sure they can be opened and closed cuts the time that water is wasted and the number of customers who are affected by a water main break.
“When we have a main break, we can go right out and shut it down. We can narrow the area of the shutdown, which enhances customer service because we don’t have big areas of the system shut off,” Pishkur said. “And it reduces the time of the main break. Water is running, so time is of the essence.”
‘Listening’ for leaks
The city is also working with a company that is testing new leak detection technology at no cost in a pilot project to show that its devices work on metal, plastic and concrete water pipe. As part of the pilot, the company is placing sensors on the water main valve boxes that “listen” for leaks. That information helps water utilities crews more precisely pinpoint the area that needs repair, which means less roadway torn up.
“We are not digging holes here and there and everywhere like we have,” Pishkur said.
If the sensors work as promised, Arlington could purchase some for its leak detection program, he said.
The combined efforts are about curbing water purchasing and treatment costs for the city, minimizing increases in customers’ water rates and finding new ways to meet the state’s long-term goal of reducing water usage per capita, Pishkur said.
“Conservation is and should be an important message to our customers. However, we should also be minimizing the loss of water in our treatment operations and system operation prior to it reaching the customers’ home,” Pishkur said.
Susan Schrock, 817-390-7639