A western Iowa city that has been dealing with brown tap water for almost a year says it has finally found a fix.
Onawa’s water has been a brownish-reddish color due to moderately high levels of iron and another metal called manganese. Resident Sarah Haptonstall says she avoids drinking her tap water.
“Some days I have clear water and some days it looks like someone got shot in my bathtub,” Haptonstall said.
Resident Tracy Erlandson says she has a house filter, but there are days where her water is fairly clear and days where her water has a brown tint to it. Around two weeks ago “it actually looked like iced tea coming out of the faucet," she said.
The city started treating its water with a chemical compound called sodium permanganate about a week ago. Onawa’s Water Treatment Plant Operator David Richardson says the compound helps the manganese particles stick together to get trapped in the treatment plant’s water filters rather than passing through.
Richardson says so far, they’ve seen immediate improvements.
“The next day we’d seen manganese levels dropping in our tanks,” Richardson said. “It’s gotten better every day since.”
Haptonstall said she has not noticed a difference in her tap water yet. She said if her water is really dark, she uses bottled water. If her water looks normal, she boils it before drinking it.
Richardson said some residents have told the city that their water is clearing up. When asked about people like Haptonstall who say they haven't noticed any improvements yet, Richardson said it could take a while to clear all of the manganese out of some of the water lines.
“Keep in mind we have over 50 dead-end water mains that have a lot of sediment in them. It will take extra time to get the sediment out of those pipes,” Richardson said.
State environmental officials and the Environmental Protection Agency say manganese is mostly an aesthetic concern and does not put human health at risk. The EPA does not enforce a maximum contaminant level for manganese, but has set guidelines for managing it for color, odor and taste.
Its recommendation is that manganese concentrations should not be over .050 mg/L. Onawa’s manganese levels last month were at .29 mg/L, Richardson said.
According to the Centers for Disease Control, overexposure to manganese through inhaling it could harm a person's kidneys, liver and lungs.
In a January interview, Keith Wilken, an environmental specialist senior with Iowa’s Department of Natural Resources based in southwest Iowa, called Onawa's manganese levels “not enforceable according to our regulations” since manganese is considered regulated for aesthetics.
Wilken said aquifers in and around Onawa and southwest Iowa do see manganese routinely.
“Most facilities do try to treat for it,” Wilken said. “It is an element that can be very difficult to get out of the water though.”
Though Onawa's brown water is considered an aesthetic issue and not hazardous to human health, Erlandson said she doesn’t feel reassured.
“Who wants to drink brown water?” Erlandson said. “I don’t care if they tell me it’s safe or not. If you have green fuzzy stuff on your steak and somebody tells you it’s penicillin and it’s safe, are you going to eat it?”
Since Onawa’s problem with brown water started in March 2018, the city replaced a filter media at the plant hoping to better trap the manganese, and rebuilt an aerator to help remove iron, Richardson said.
According to a notice from the city posted to social media on Wednesday, Onawa plans to install up to 50 flushing hydrants across its water lines this spring to flush iron and manganese deposits completely out of distribution lines and dead ends in the system.