Manganese occurs naturally in drinking water and can be found in rocks and soil. People need some manganese to stay healthy, but too much can be harmful.
Scientists are still learning about the impacts of high levels of manganese in drinking water. Regulating agencies like the Environmental Protection Agency (EPA) continue to collect data to analyze and determine if regulations will be needed in the future.
In 2018 the Minnesota Department of Health (MDH) developed guidance levels for manganese in drinking water.
For infants one-year-old and younger who drink tap water or drink formula made from tap water, safe drinking levels for manganese in drinking water is 100 micrograms per liter (ug/L) or less.
For people over one year old, a safe level of manganese in the drinking water is 300 micrograms per liter (ug/L) or less.
Public water systems are not required to meet these guidelines, and they are not required to treat drinking water for manganese as it is not a primary drinking water standard.
Manganese in Monticello
The City has five drinking water wells. Based on testing, the municipal water supply meets all Safe Drinking Water Act standards; however, some of the City's municipal drinking water wells have manganese levels above MDHs recommended health guidelines.
The City will continue to frequently test the drinking water in Monticello. We're also committed to pursuing options for residents and the city as a whole to reduce manganese in the water.