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Monday, March 4, 2024
March 4, 2024

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Complaints about manganese in Longview water linger a decade after switch


LONGVIEW — Dwight Sutherland turned on his bathroom sink and began lightly scrubbing on the faucet spout. Tiny black chips flaked off the faucet and whisked down the drain.

Sutherland’s family has lived on Nevada Drive for 32 years. The house is just north of Longview’s city limits but gets water from the city via the Beacon Hill Water and Sewer District.

For the last decade, Sutherland said he’s been fighting against the small particles of manganese that have come through his pipes. Not all of his neighbors have had the same issue, which Sutherland found hard to believe.

“They don’t know how to look for it. You wouldn’t even know it until you get a drop of black slime in your glass,” Sutherland said.

Longview was flooded with water quality complaints after it first made the switch to a new source a decade ago. Now, water system officials in Longview and Beacon Hill said complaints have trickled down to a handful per year. Most revolve around manganese, especially the way it comes off old pipes and water mains.

Manganese is a non-toxic raw element that is largely invisible as the water flows but can leave behind a notable residue. At the Sutherland’s home, he said it builds up enough in a week to slow water flow from faucets, and enough over a year to start blocking the holes in the family’s washing machine. On occasion, manganese buildups will cause a drop of black slime to fall from faucets, he added.

The wells that are the source of Longview’s water have between 0.5 and 0.8 milligrams of manganese per liter of water. If not filtered through the water plant, those raw manganese levels are twice as much as the Environmental Protection Agency and the state Department of Health consider potentially dangerous for infants.

That much manganese does not make it into the city’s water. Longview’s last two water quality reports to the Washington Department of Health, provided in 2016 and 2017, showed manganese levels in the main water system are below 0.01 mg/L. Longview’s water treatment plant uses pressure filters to remove manganese and iron from the water until they’re well within safe levels.

“As much as we want to filter out all those minerals, you can’t do anything to 100%,” Longview’s Public Works Director Ken Hash said.

What is manganese?

Manganese is considered a secondary contaminant for water, meaning it isn’t considered a health risk at the same level as arsenic, lead or chemical contamination. The standards for secondary contaminants are not enforced by the EPA because they generally affect the water’s appearance and taste instead of health.

The Washington Department of Health issues a “do-not-use” advisory for water systems with high levels of manganese, which is 1 mg/L for the general population and 0.3 mg/L for infants. The department has never issued an advisory for Longview.

For decades Longview had pulled its water from the Cowlitz River. The city began looking for a new source because of the high levels of volcanic silt in the river since Mount St. Helens erupted. The excess silt broke the filters at the Fishers Lane Water Treatment Plant on multiple occasions in the mid-2000s.

The Mint Farm Water Treatment Plant, opened in 2013, taps into an underground aquifer hundreds of feet below the Mint Farm section of town. But the groundwater quality sampling reports, which are posted on Longview’s website, have found manganese at significant levels in the test wells and the source wells.

An analysis of EPA water quality reports by Public Health Watch estimates about 2% of public water systems had more than 300 mg/L of manganese. Longview was not included in the review.

Dell Hillger, district manager of Beacon Hill Water and Sewer District, said part of the issue is that Mint Farm and Fishers Lane are on opposite sides of town. For a lot of the city’s water mains, that meant the water from the new treatment plant was going the opposite way it had gone for decades prior. Layers of manganese and iron that had built up in the pipes could be chipped off by the new flow.

“When you reverse the flow, a lot of those elements start coming off of the pipes,” Hillger said.

Hillger said the manganese that could get to individual homes depends on the age of the pipes, the home’s location, and whether the house’s water filter has been regularly cleaned.

Safe but present

Hillger said Beacon Hill only tests for the primary required contaminants to reduce customers’ expenses, so the district doesn’t track the manganese levels regularly.

“We’re trying to find a balance between the quality and the costs to the consumer. We have people now that are struggling to pay their water bill. It’s tough to add another $10-$15 a month to their water bill,” Hillger said.

Longview installed a dissolved oxygen system to improve the water’s silica issues a few years ago. Hash said the only way Longview could remove even more manganese from the water is reverse osmosis, where water is run through a filter at high pressure to concentrate the impurities into a smaller portion of the water.

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“One gallon would go to the sewer system and one gallon would be used for drinking water. We average about 4 million gallons a day, so it’d have to jump up to 8 million gallons,” Hash said.

The additional system would also be massively expensive. In 2014 city engineers looked into systems to soften the water quality and improve issues like manganese. At the time, leaders estimated the system would cost at least $35 million to add to the Mint Farm Water Treatment Plant, which is more than the plant’s total construction cost.

At individual homes, a water filtration or re-circulation system would be the best way to further limit the effects of manganese. Sutherland wasn’t happy with that answer.

“You shouldn’t have to do that to get clean water,” Sutherland said.