Groundwater Standard Recommendations (Cycle 10)

In June 2019, DHS provided the DNR recommended groundwater standards for 27 substances.

This was the 10th time that Department of National Resources (DNR) has requested the Department of Health Services (DHS) to develop recommended groundwater standards for the protection of public health. The table below summarizes these recommendations and additional details can be found in the letter sent to the DNR. DNR is currently undergoing rulemaking to adopt these recommendations.

Recommended Groundwater Standards
Substance New or Existing

Enforcement Standard
Recommended Valueiii

Preventive Action Limit
Recommended Valueiii

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 and
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.
iii. The recommendations included in this table are reported as micrograms per liter (μg/L) or nanogram per liter (ng/L). You can find more information about these units on our chemicals page.


The Department of Agricultural, Trade and Consumer Protection (DATCP) has fact sheets with information on the pesticides included in Cycle 10.
Our PFAS webpage has information on sources and health effects of PFAS.
The Agency for Toxic Substances and Disease Registry (ATSDR) has fact sheets on health risks of various substances.


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Last Revised: March 25, 2021