Manganese is a naturally occurring element found in rocks and soil and is often found in Minnesota ground and surface water. Your body needs some manganese to stay healthy, but too much can be harmful. Learn more by visiting the MDH webpage and searching for Manganese in Drinking Water.
Manganese is unregulated and does not have an enforceable standard. However, the MDH recommended health guidelines are:
If you have an infant who drinks tap water or drinks formula made with tap water, a safe level of manganese in your water is 100 parts per billion (ppb) or less.
If you have an infant who never drinks tap water or formula made with tap water, a safe level of manganese in your water is 300 ppb or less.
If everyone is more than one year old, a safe level of manganese in your water is 300 ppb or less.
The City requested testing from MDH to better understand manganese levels for all City wells. Below are the results from the December 31, 2019 testing (For the most recent water testing results see Manganese Testing in City Water Supply (PDF)).
Well Number 1 158 ppb
Well Number 2 527 ppb
Well Number 3 322 ppb
Well Number 4 84 ppb
Well Number 5 143 ppb
Well Number 6 408 ppb
The City's municipal water supply is a mixture of water from all six wells. The water mixes in water mains and towers and then travels to customers' taps. The City cannot know the level of manganese at any given drinking water tap.