DIXON, Iowa — Dixon isn’t alone in dealing with nitrates.

The northwestern Scott County town was notified by the Iowa Department of Natural Resources on Dec. 2 that nitrate levels in the municipal well were higher than the acceptable level for the third time in 12 months, requiring corrective action.

The DNR found nitrate levels of 11 milligrams per liter during routine testing, higher than the recommended limit of 10 milligrams per liter for infants younger than 6 months. The discovery prompted the agency to warn residents to not use the city’s water for infants younger than 6 months.

“What we have agreed with the EPA to do is that when there are these three violations occur, a town is required to treat the water and remove the nitrates,” said Ryan Stouder, an environmental specialist for the DNR, “or consider an alternative water source.”

Nitrates can come from decomposing plant material or animal manure. They have been a problem across the state for a long time, Stouder said.

Des Moines has the largest nitrate filtration system in the world at its water treatment plant. Dixon is one of 221 communities across the state being monitored by the DNR because the nitrate level in their water supplies exceed 5 milligrams per liter.