Arsenic is a naturally occurring element found in soil and bedrock throughout Wisconsin. Under certain conditions, arsenic can be released into groundwater and enter water wells. Long-term exposure to arsenic in drinking water is known to increase risks of skin, bladder, lung, liver, colon, and kidney cancer. Other health effects may include blood vessel damage, high blood pressure, nerve damage, anemia, stomach upsets, diabetes, and skin changes.
How to find out if your water is safe to drink
You cannot smell, taste or see arsenic in your private well water. The only way to know if your drinking water contains arsenic is to have a water sample from your private well tested by a certified laboratory.
Get started testing your water
Contact a certified laboratory that can test your water for a specific contaminant.
Collect a water sample properly
The laboratory you work through will provide you with a water sampling kit. It's very important to make sure you follow their sampling directions.
Watch a demonstration showing the DNR’s recommended methods for of how to properly collect a water sample that will yield accurate results.
What to do when your test results arrive
The federal drinking water standard for arsenic is 10 parts per billion. For private residential wells, there is no state or federal requirement that you stop using your water, regardless of the arsenic level. However, if your arsenic level is more than 10 ppb, the Wisconsin Department of Health Services (DHS) recommends that you stop using your water for drinking or food preparation.
- Arsenic in Well Water: Understanding Your Test Results
(Wisconsin Department of Health and Family Services publication)
What to do about high arsenic levels in your well
There are some options for well owners when well water tests high for arsenic.
- Approved arsenic treatment devices
The list contains treatment devices approved by the Department of Safety and Professional Services for the removal of arsenic. Two categories of devices are defined, Point of Use (POU) and Point of Entry (POE). POU devices are used to treat water at the point of use such as a single tap. Distillation units provide safe water in batches while Reverse Osmosis (RO) units can be installed on a single tap. POE treatment systems treat all the water entering the home. All types of systems must be properly installed and maintained to reliably remove the arsenic from your drinking water.
Drilling a new well when old well has extremely high levels of arsenic
Drilling a new well may be necessary for extremely high levels of arsenic. Special well construction guidelines are available from DNR.