Monitoring Missoula’s nearly 340 miles of water mains takes a combination of technology, complaint tracking and listening closely to fire hydrants.
One full-time employee’s job is finding and investigating leaks, which includes placing devices on valves and listening for excess noise, said Andy Schultz, city engineer for utilities.
“Making that concerted effort is paying off,” he said. “We’re seeing a reduction in pumping needs.”
Since the city gained possession of the water utility in 2017, it’s invested considerably in replacing and repairing the aging infrastructure with a focus on leak reduction, Schultz said. Public works has made progress, but keeping up with hundreds of miles of water mains that grow older each year is a struggle.
“A lot of municipalities around the country are facing this crisis where we’ve got aging infrastructure and not enough funds to keep pace with it,” Schultz said.
As that backlog swells, Missoula’s in deeper water than most.
Investments in Missoula’s water system lagged under private ownership, and Mountain Water Co. deferred upgrades further during the condemnation case. In 2014, the city of Missoula used eminent domain powers and initiated condemnation proceedings to force Mountain Water’s parent company to sell the utility to the city.
At the time, almost half of the water mains were 45 years old or older and 20 percent had exceeded their useful life, according to city testimony included in the preliminary condemnation order issued by District Court Judge Karen Townsend in 2015. Mountain Water’s own studies showed its rate of pipe replacement was not sustainable nor enough to prevent water main failures, the city noted at the time.
Just under nine miles of water main were laid more than 100 years ago, around the time of the first Winter Olympics and the introduction of iodized table salt.
The city showed that the water system leaked at a rate of 50 percent or more—an estimated 7,000 to 8,000 gallons per minute. That leakage rate, as measured by the American Water Works Association Infrastructure Leakage Index, was in the 18 to 20 range, compared to the 3.57 average rating, the order states.
During the trial and ownership transition from 2015 to 2018, estimated water leakage increased before dropping in 2019 and 2020, according to a recent public works press release. After going back up during the first two years of the pandemic, leakage dropped in 2022 and 2023 as repairs and replacements picked up, a December 2023 leak study showed.
From 2004 to 2014 Mountain Water spent less than $1 million per year to replace water mains, only half the amount of pipe its own analysis determined was the minimum necessary, according to the condemnation order. Bringing the water system up to industry standards would take between $66 million to $95 million, the city estimated at the time.
In the last six years, Missoula has spent $45 million in system improvements, including nearly $20 million to replace 8.7 miles of water main, according to public works. The city is inching toward its goal to replace 1 percent of the 340 miles of water main annually. It replaced 2.8 miles in 2023, and another 2.8 miles will be installed or replaced during the 2024 construction season, its release said.
While Missoula’s productive aquifer means its water supply is not as constrained as many areas in the West, higher rates of leakage have consequences.
“Pumping water up, there’s a cost there, and if it’s leaking back down into the ground, that’s just wasted energy,” Schultz said. “When looking at it from a climate standpoint, a greenhouse gas reduction standpoint, we’re trying to look at every drop of water we can reduce.”
In 2009, Mountain Water spent $588,888 to pump and treat water that leaked out of the system, according to the city’s testimony in the condemnation case.
Over the last two years, the city reports a 16 percent reduction in leakage. That saves nearly 205 million gallons of water per year and reduces the city’s greenhouse gas emissions by about 160 metric tons of carbon dioxide equivalents, the press release said. That’s the same amount of emissions as 38 gas-powered passenger vehicles driven for one year, according to the U.S. Environmental Protection Agency’s calculator.
A water main’s age can make it more likely to leak, and Missoula still has pipes dating back to the start of World War I, according to public works.
Just under nine miles of water main were laid more than 100 years ago, around the time of the first Winter Olympics and the introduction of iodized table salt. About 22 miles of pipe are 75 and older, making them the second-highest priority for replacement.
Top priority for replacement are not just those that are a century old—although many do fall into this category—but pipes that tend to leak because of their material, Schultz said.
Many of the oldest water mains installed in the 1910s and 1920s are made from kalamein, a standard steel pipe immersed in a molten alloy, according to the city’s 2018 Water System Master Plan. While the pipe has held up relatively well, the joints have a tendency to leak, the document states.
The city’s “steel invasion” water mains, made from a thin-walled steel pipe originally manufactured during World War II and installed between 1946 and 1950, often spring small leaks, Schultz said.
These pipes are located throughout the older parts of Missoula, with those 75 and older the most common and widespread in the University District, Rose Park and Riverfront neighborhoods, according to a map included in the 2018 master plan.
Stretches of kalamein pipe remained downtown, in the University District and the Riverfront, Westside and Northside neighborhoods when mapped for the master plan, with some since replaced. Rose Park, Riverfront, south end of University District and parts of Franklin to the Fort had some WWII-era steel pipe at the time.
More of these aging and problematic water mains are scheduled for replacement this year, including those installed between 1914 and the 1940s along East Beckwith Avenue, South Fourth Street West, East Front Street and West Pine Street, according to public works.
But neither the age nor the material of a pipe necessarily indicates that it’s leaking, and sometimes newer pipes need repairs, too. Schultz said there are significant leaks across Missoula. Residents often notify the department of telltale signs such as water pooling in their yards or reduced water pressure, which helps pinpoint more exact locations.
With so many aging and leaking pipes, public works considers several criteria when scheduling replacements, including the potential consequences of a water main break and if a project is in an underserved neighborhood, Schultz said.
He added that the water and street departments coordinate projects when possible to avoid tearing up the same street twice, which helps save money as construction costs surge.
“The inflation we’ve seen is even higher because there is a bunch of federal money in the market, so a lot of communities are doing a lot of investment in infrastructure with a pretty constrained pool of contractors and materials,” Schultz said.
The water department is funded solely by ratepayers and doesn’t receive property tax revenue, Schultz said.
In 2021, Missoula City Council approved utility rate increases for the following three years to account for inflation and pay for necessary improvements. Before then, water rates hadn’t changed since 2011.
The average residential customer’s monthly water bill increased from $41.20 in 2021 to $43.36 2022, to $45.53 in 2023 and $47.81 in 2024, according to the city. Overall, the increases to water, wastewater and stormwater rates bumped the average customer’s monthly utility bill from $62 in 2021 to $73.43 in 2024.
Missoula used about $5.4 million in American Rescue Plan Act federal relief money on water main replacements, matched with water department savings. Public works receives low interest rate loans through the state’s drinking water revolving loan fund to cover the full cost of pricy projects, Schultz said.
“If we don’t continue to reinvest in our water system we’re going to have failures and they’re going to be more dramatic and more frequent,” he said. “Ultimately, I think that as we are able to reduce the amount we’re pumping, then we’re not paying as much for the water we’re drinking, not damaging our other infrastructure with leaks, and reducing our electrical demand.”
