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The DNR will be having a public comment period. To learn more about the rule-making process and how to submit comments, go to DNR's Summary of Wisconsin's Groundwater Rule webpage.
In Wisconsin, state groundwater standards are used to protect and ensure clean groundwater resources. More than two-thirds of Wisconsin residents use groundwater for their drinking water, whether through a private well or public water system. The development of state groundwater standards is a collaborative process involving multiple state agencies.
Our primary responsibility is to develop groundwater standard recommendations for substances that represent a public health concern (when requested by the Wisconsin Department of Natural Resources). The Department of Natural Resources can propose rules these new or revised standards based on DHS recommendations. Check out our Protecting Groundwater fact sheet to understand more about the DHS process.
The table below summarizes our recommendations for groundwater enforcement standards and preventive action limits that were provided to the Department of Natural Resources on June 21, 2019. In the coming months, there will be a period for the public to give input on these proposed standards to the Department of Natural Resources.
|Substance||New or Existing||
Preventive Action Limit
|1,1-Dichloroethane||Existing||No change||850 µg/L||No change||85 µg/L|
|1,2,3-Trichloropropane||Existing||0.3 ng/L||0.03 ng/L|
|1,4-Dioxane||Existing||0.35 µg/L||0.035 ng/L|
|Aluminum||Existing||No change||200 µg/L||No change||20 µg/L|
|Bacteria (E. coli)||New||n/a||0||n/a||0|
|Bacteria (total coliform)||Existing||No change||0||No change||0|
|Barium||Existing||No change||2,000 µg/L||No change||400 µg/L|
|Boron||Existing||2,000 µg/L||400 µg/L|
|Clothianidin||New||n/a||1,000 µg/L||n/a||200 µg/L|
|Cobalt||Existing||No change||40 µg/L||4 µg/L (ii)|
|Dacthal MTP (monomethyl tetrachloroterephthalic acid) and
Dacthal TPA (tetrachloroterephthalic acid) (i)
|New||n/a||70 µg/L||7 µg/L (ii)|
|Glyphosate||New||n/a||10 mg/L||n/a||1 mg/L|
|Glyphosate AMPA (aminomethylphosphonic acid)||New||n/a||10 mg/L||n/a||2 mg/L|
|Hexavalent chromium||New||n/a||70 ng/L||n/a||7 ng/L|
|Imidacloprid||New||n/a||0.2 µg/L||n/a||0.02 µg/L|
Isoxaflutole diketonitrile (DKN)
|New||n/a||3 µg/L||n/a||0.3 µg/L|
|Isoxaflutole benzoic acid (BA)||New||n/a||800 µg/L||n/a||160 µg/L|
|Molybdenum||Existing||No change||40 µg/L||4 µg/L (ii)|
|PFOA (perfluorooctanoic acid) and
PFOS (perfluorooctane sulfonic acid)
|New||n/a||20 ng/L||n/a||2 ng/L|
|Strontium||New||n/a||1,500 µg/L||n/a||150 µg/L|
|Sulfentrazone||New||n/a||1,000 µg/L||n/a||100 µg/L|
|Tetrachloroethylene (PCE)||Existing||20 µg/L||2 µg/L|
|Thiamethoxam||New||n/a||100 µg/L||n/a||10 µg/L|
|Thiencarbazone-methyl||New||n/a||10 mg/L||n/a||2 mg/L|
|Trichloroethylene (TCE)||Existing||0.5 µg/L||0.05 µg/L|
i. These substances are combined with dacthal’s existing enforcement standard.
ii. Although DHS is not recommending a change in the enforcement standard for this substance, we are recommending a change in the preventive action limit.
1 µg/L (microgram per liter) = One part per billion (ppb)
1 ng/L (nanogram per liter) = One part per trillion (ppt)
1 mg/L (milligram per liter) = One part per million (ppm)
See our chemical webpage for more information on conversions.
- Enforcement standard - level of a substance in groundwater that is used to protect public health or welfare and the level at which the sources of the substance might be regulated.
- Preventive action limit - level of a substance in groundwater that is used by regulatory agencies to determine when action may be needed so that levels do not reach or exceed the enforcement standard.
- Carcinogen: Cancer causing
- Mutagenic: Causes birth defects
- Teratogenic: Causes DNA damage
- Interactive effects: Can affect the toxicity of another substance or its toxicity can be affected by another substance.
- Department of Agricultural, Trade and Consumer Protection (DATCP) Pesticide Database Search: Lookup pesticide names by active ingredients.
- Agency for Toxic Substances and Disease Registry (ATSDR) ToxFAQs: Find fact sheets on health risks of various substances.