In early March of 2019, the City of Bagley made the news when high levels of the trace mineral manganese were discovered in their city water supply. Their water was declared “undrinkable” by the EPA and the IDNR. Historically, manganese testing has not been required and is not an enforceable contaminant. This is probably going to change.
What is manganese?
Manganese is a naturally occurring trace mineral found in ground water and is closely associated with iron. Essential to good health it plays a major role in many bodily functions (dailydosage.com/manganese-dosage/). While present in drinking water, the amount is insignificant to play a major role in human health.
Currently, the EPA recommends levels not to exceed .3 mg/L (milligrams per Liter) for infants and 1.0 mg/L for adults. Starting around the level of 0.05 mg/L the major issues are esthetics, mainly discoloration and a metallic taste. Other trace minerals may also cause discoloration and a metallic taste. Older buildings that have partial or total plumbing comprising galvanized water lines will have the same issues of discoloration and a metallic taste.
The City of Colfax uses ground water exclusively from two wells located in the west end of town. The city recently had both wells tested for manganese level by Keystone Laboratories in Newton. One well test resulted in a level of 0.005 mg/L and the other tested at less than 0.005 mg/L.
So even though the water is considered moderately hard, it is definitely safe for drinking.