Discovering that your drinking water well has high levels of nitrates can be discouraging. However, knowing the nitrate level is an important step in maintaining the health of everyone in your household. The US Environmental Protection Agency states that drinking water with nitrate levels over 10mg/L is not safe for pregnant women and young children who are especially susceptible to methemoglobinemia (“blue baby syndrome”). There are possible links between high nitrates in drinking water and miscarriages in people and animals. It is recommended that all avoid long term consumption at these levels.
Nitrate levels between 2mg/L and 10mg/L are evidence of human impact on the drinking water in the area. Sometimes nitrates in drinking water can also indicate the presence of other contaminants in the water. Nitrates can come from agricultural fertilizer, lawn fertilizer, septic systems, and animal waste.
Long term, reducing nitrogen in the environment is the only way to remove nitrates from drinking water. This could include properly closing wells that are no longer in use. Well abandonment is a requirement in Fond du Lac County and can prevent new wells from being contaminated. Short-term solutions include changing the depth of the well, drilling a new well, using water from another source, connecting to a public water supply, or installing a water treatment device (reverse osmosis, distillation, or anion exchange).
The State of WI has created a list of Approved Water Treatment Devices . These systems have been tested to ensure that they really do remove the contaminants they claim to remove.
For more information:
Water and Environmental Analysis Lab (of UW Stevens Point and UW-Extension)
Nitrate in Drinking Water
Interpreting Drinking Water Test Results (UW-Extension publication, PDF)
Supply (UW-Extension publication, PDF)
Interpreting Drinking Water Quality Results
Tests for Drinking Water from Private Wells (WDNR Publication, PDF)