Starting last Thursday, water users in several communities including Clearfield, West Point, Layton and Kaysville reported a yellow tint to their water. The Weber Basin Water Conservancy District reported that the water was safe. This week, officials have a better idea of what caused the yellowing of water throughout the area.

Darren Hess, assistant general manager with the water district, told the Standard-Examiner that officials are confident they know the culprit.

“We’re thinking there was probably some water that had some high manganese that came through the system,” he said. “That’s a secondary MCL (maximum contaminant level), so it’s not actually watched over by the EPA because it has nothing to do with the safety of the water. … It just has to do with the aesthetics of the water — what it looks like.”

A press release sent out by the district on Thursday added a bit on how manganese can enter the water system.

“The District has tested several of these water samples and has found the water to be Safe to Drink and meets all EPA water quality standards,” the release said. “In a few of these samples, the District has found the manganese level to be elevated which has resulted in some yellow tinting to the water. Manganese is a mineral that is found naturally in many surface and groundwater sources. Water passing through soil and rock in the watershed can dissolve minerals, such as manganese, and carry them to the water treatment plants.”

The release added that the District has equipment that would usually help with the discoloration that was offline for a time due to maintenance.

“The District typically runs its ozone system throughout most of the year which oxidizes the manganese and filters it out in the water treatment process. The District shut down its ozone system two months ago for necessary repairs because it historically has not seen high manganese levels coming from the watershed during the winter months.”

According to the press release, the ozone system has been reactivated with the completion of repairs.

Hess said that a spike in manganese large enough to discolor water isn’t unheard of, but it is abnormal for this time of year.

“We can see some elevated levels, usually in the spring and summer when we have runoff because there’s manganese in sediments and silts on the bank of the river system,” he said. “Manganese is everywhere, so when we see high flows coming down the river, we’ll see high events in the spring and summer. We treat it — it’s easy to treat —  but we just don’t see that this time of year. It was really strange. I haven’t seen that in my 25 years in the winter time.”

He added that while it’s unknown why there was a large spike of manganese in the water system at this time of year, residents shouldn’t see it again in the near future.

“It’s all gone through the system at this point,” he said. “It’s a done deal.”