Most Helena residents, at some time or another, have awakened to find an ugly sink or shower surprise: discolored water, tinted red and brown, flowing from their faucets.

Officials have long voiced rational yet anecdotal explanations for the unsightly problem, and numerous independent lab tests over the years have deemed the water safe for consumption.

Yet, until now, they’ve never had concrete answers or solutions.

City officials and engineers from HDR Engineering on Friday announced the results of a detailed analysis of Helena’s water distribution system, made up of 206 miles of pipes, and the city’s two water-treatment plants, along with several proposed solutions set to begin in coming months.

The cause of the problem is rooted both in the delicate chemical dance water-plant operators negotiate to treat Helena’s water, and in the roughly 125-year-old history of the city’s water mains. The proposed fixes, in turn, also range from microscopic to systematic.

Officials will alternately adjust their treatment processes and run a series of 2,000-gallon-per-minute hydrant flushes in neighborhoods across the Queen City this summer, seeking to address the source of the problem and scour buildups of sediments and minerals in the old mains.

The problem won’t disappear immediately, officials said, but the two-pronged approach is the first step toward consistently clear water in Helena homes.

The Ten Mile Water Plant treats the majority of the water Helenans consume, drawing from near the bottom of the 567-million-gallon Chessman Reservoir near the headwaters of Tenmile Creek.

Engineers recently discovered the water coming from Chessman contains a significant amount of dissolved manganese. When the water is treated, the manganese partners up with oxygen molecules and forms a fine particulate, which settles out and coats the insides of low-flowing residential water mains.

Some of the city’s pipes, particularly downtown and in upper west side neighborhoods, are made of iron. As the pipes corrode, rust forms in tiny, hard scales, adding to the mix of manganese and old sediments inside the lines.

Then, when the water pressure changes in the pipes or the flow reverses — due to new water connections, main breaks, or other causes — the red-brown mix of minerals and dirt swirls through the system and enters Helena households.

Officials knew about the rust and sediment in the city’s pipes, but the manganese-oxide problem was an unexpected discovery. The “nuisance compound,” as HDR engineer Steve Reiber calls it, isn’t a health concern.

“Manganese is not a public-health issue,” he said in a phone interview from Seattle.

“I don’t say that to downplay the seriousness of the problem,” Reiber added. “When people see discolored water, they have a right to be concerned.”

Water-plant operators already deal with what Reiber calls “a fairly tricky water-chemistry balance.” They must disinfect the water to make it safe for consumption while also addressing various chemical factors to deal with the corrosion of city water mains and household plumbing.

To address the problem, the city must make a few improvements to the Ten Mile Plant and adjust the knobs in its water-treatment process.

Officials plan to rebuild the plant’s old intake structures, which bring water into the facility from the reservoir. When the plant was built, it could take water from varying depths in Chessman, but some intakes have been damaged over the years.

The city now only draws from the bottom of the lake, where dissolved manganese is most prevalent. Officials will revive an old plan to rebuild the intakes closer to the surface, bringing less manganese into the plant.

Officials also plan to purchase solar-powered aerators later this month. When installed at the reservoir, the equipment will cut down on algae growth and help address the manganese concentrations.

Reiber also suggested the city adjust the acidity and alkalinity of water coming out of the plant to strengthen existing iron-oxide scales that have built up within the pipes, making them more resistant to changing water flows.

“You want (the layer of iron-oxide) to be thin, you want it to be hard, and you want it to be as impervious as you can make it,” Reiber said.

To address the existing sediments and minerals in the city’s water pipes, workers this summer will isolate four- to six-block areas of Helena and flush the lines by turning on city fire hydrants.

Officials hope the increased flows from the hydrant flush — 400 times the typical household water flow — will peel off the problem particles.

“We can really stir things up,” Public Works Director John Rundquist said.

Work likely will begin in older parts of town and progress from west to east, pushing the sediments toward the Missouri River via the city’s storm-sewer system. Officials plan to flush the system every three or five years to keep the problem from recurring.

Water Maintenance Superintendent Kevin Hart said his workers will notify neighborhood residents prior to the flushes, using door-hanging cards to ask citizens to reduce their water usage during the project. There’s a chance some of the sediments could flow into households if the faucets are turned on during the flush, he and Rundquist said.

Residents shouldn’t lose water service during the project but may experience a drop in pressure.

City Manager Tim Burton and Water Superintendent Don Clark said the study’s results have provided a measure of relief in city offices. Officials and residents have seen discolored water coming from Helena taps for decades, but the city hadn’t been able to address or explain the problem.

Though the water has always proven to be safe to drink, no one likes to see dirty water coming from the city’s system, they said.

City commissioners, after an extended bout of colored-water problems this winter, asked Burton, Rundquist and Clark to explore the issue. The city paid HDR $10,000 to analyze the problem and find a solution.

Reporter Larry Kline: 447-4075 or larry.kline@helenair.com