Following a water main break on Case Avenue on July 28, some area residents began experiencing brown water flowing from their taps. The next day, the borough advised residents not to drink the discolored water.

However, the broken pipe was only indirectly responsible for the murky water.

The discoloration was caused by a mineral called manganese, according to Tom Wetor, director of the Public Works Department. Over time, manganese builds up in the water pipes, creating deposits.

These deposits can become dislodged by changing water flows that occur when water is used by fire trucks or, say, when a large area of downtown’s water is shut off to repair a broken pipe, such as last week’s incident.

The community experienced two more water line breaks on Sunday: One at Reid and Mission streets, and one on Zimovia Highway between Ash and Wood streets. 

While this mineral is naturally occurring in soil and water, and in nuts, seeds, grains and green leafy vegetables, and is fine for the human body in low doses, the borough’s water quality notice stated it can be detrimental in high doses for adults, posing a much higher risk for infants in lower doses.

The borough’s notice said the water can still be used for showers, laundry and even brushing teeth.

“It’s when you’re seeing brown water, tea-colored water, coffee-colored water at your tap that is likely high in manganese,” Wetor said, “And so when you’re getting those pockets of brown water, discolored water, the best thing to do is flush your system.”

Brown water events are usually short-lived and can be resolved by flushing the system by turning on household taps until the water runs clear. According to Wetor, shutting down larger areas of the system can require longer flushing periods to clear the pipes.

“Part of the reason why we think it was as bad as it was because of how much of town we had to shut down to make this water main repair.”

The borough advises that boiling water will not remove the manganese.

The borough’s July 29 announcement noted that while the manganese levels last week exceeded federal standards, “tests performed on our normally clear drinking water are far below this value.”

Wetor explained that the manganese deposits are likely due to a change in how the borough filters its water following the transition to a new treatment plant last year.

The old system used ozone to essentially shock the water, oxidizing the manganese and suspending it in the water and then filtering it out. In the new system, the water passes through a filter to remove biological material first, then chlorine is added to ensure the water is disinfected and safe for consumption.

This chlorine causes the manganese to oxidize after the filter, allowing it to collect in the pipes in areas of low flow, like dead-end streets.

The reason for the change was that the old system was not removing as much biological material from the water as it should have, leading to negative interactions with the chlorine, which is required by law in municipal drinking water. Wetor said the new treatment system is removing 90% more particulates from the water than the old system.

Manganese deposits aside, the new plant has been successful at delivering high-quality clean drinking water to Wrangell taps, he said. 

Residents with any concerns about water quality can access the annual water quality report released each June on the borough website or reach out directly to Public Works at 907-874-3904.

“People should be informed about this,” Wetor said, “It’s their drinking water.”