Long-term exposure to arsenic, even at low levels, is associated with adverse health effects, including cancer of the
bladder, lungs, skin, kidney, nasal passages, liver, and prostate. Other possible health effects include cardiovascular
disease, developmental and reproductive effects, diabetes, and skin changes. The risks from exposure to arsenic depend on
many factors, including the type of arsenic, the duration and level of exposure, and individual susceptibility, which can
depend on things like age and genetics.
For more information, visit MN Public Health Data Access: Arsenic in
- Of the 64,793 new private wells sampled, 48.4 percent had arsenic at concentrations above the typical
detection limit of 2 µg/L and 11.3 percent had arsenic above the health-based value of 10 µg/L.
- These data are limited to new private wells constructed and tested August 2008 to
December 2021. Therefore, these data are not representative of all private wells in Minnesota.
- The county arsenic values provide important information regarding arsenic concentrations and
distribution in private well water in Minnesota. The extent of the Des Moines Lobe Till can also be used to identify areas
where higher arsenic concentrations may be found. However, the county data and till information cannot be used to predict
arsenic concentrations in individual wells. The only way to know the arsenic concentration in a well is to have the well
- Data are not currently available in the map for other contaminants of concern in private wells,
such as bacteria and nitrate.
- Counties with less than 20 total wells tested should be interpreted with caution; the data may
be unstable because it can change dramatically with the addition or subtraction of one well. Unstable data are displayed
with hash-marks on the map and an asterisk (*) next to the county name on the pop-up display and table.
- For additional information pertaining to the data, please visit the
"About the Drinking Water Quality Data" page.
- Minnesota Department of Health Well Management Database