Groundwater Standard Recommendations (Cycle 10)

DHS continues to support the recommended groundwater standards for PFAS and other hazardous substances.

On February 23, 2022, the Natural Resources Board did not approve the Cycle 10 groundwater standards rule for adoption.

DHS is committed to protecting the people of Wisconsin from groundwater contamination. We continue to work closely with our sister agencies to make progress on adopting standards for the protection of public health.

The Wisconsin Department of Natural Resources (DNR) is currently working to determine next steps for these standards.

While the NRB's decision stopped the rule-making process, it did not change DHS' scientific evaluation of the health impacts of these substances. DHS’ recommended standards are set to protect all people from the health effects of substances in groundwater. DHS' establishes these recommendations used the best available science and the process laid out in State Statute.

Background

In March 2018, the Wisconsin Department of Natural Resources (DNR) requested that the Wisconsin Department of Health Services (DHS) develop groundwater standard recommendations for 27 substances that may be present in Wisconsin's groundwater. This process is known "Cycle 10" because it is the 10th time that DNR has made such a request. In June 2019. DHS provided DNR with recommended standards for the 27 substances. At that time, DNR began the process for adopting these standards into administrative rule. DNR's Cycle 10 page has more information on the steps in that process.

In December 2021, DNR held a public hearing and public comment period on the proposed rule language. They received more than 280 comments. DHS provided support for a handful of health-related comments. In response to these comments, DHS made several typographical changes to the scientific support documents for the recommended standards and revised the standards for two substances - molybdenum and thiencarbyl-methyl. This letter summarizes the changes that DHS made to the recommended standards in response to the public comments received.

DHS' Recommended Groundwater Standards

Inorganic Substances

Aluminum

Aluminum is a naturally occurring metal that is used in a variety of industrial and commercial applications. Aluminum may affect reproductive organs, brain, and kidney function. Certain groups may be at a greater risk for aluminum toxicity such as infants and people with impaired kidney function.

  • Recommended enforcement standard = 200 µg/L
  • Recommended preventive action limit = 20 µg/L

Wisconsin currently has groundwater standards for aluminum. DHS recommends lowering the preventive action limit for aluminum due to potential carcinogenic (cancer-causing) effects.

Learn more

DHS' cycle 10 (aluminum) fact sheet has an overview of the recommended standards and steps to take if high levels are found in drinking water.

DHS' cycle 10 support document (pages 274-292 for aluminum) has a detailed summary of the scientific studies reviewed and rationale for the recommended standards.

Barium

Barium is a naturally occurring metal found in many types of rock. Barium can also get into the environment from power plants and vehicle paints and from drilling mud. Barium may cause gastrointestinal disturbances and muscular weakness.

  • Recommended enforcement standard = 2 mg/L
  • Recommended preventive action limit = 0.4 mg/L

Wisconsin currently has groundwater standards for barium. DHS recommends no change to the standards for barium.

Learn more

DHS' cycle 10 (barium) fact sheet has an overview of the recommended standards and steps to take if high levels are found in drinking water.

DHS' cycle 10 support document (pages 303-313 for barium) has a detailed summary of the scientific studies reviewed and rationale for the recommended standards.

Boron

Boron is commonly found in soil and rocks. Boron compounds are used in production of a number of products. Exposure to large amounts of boron can affect the stomach, intestines, liver, kidney, and brain and may impact reproduction and development.

  • Recommended enforcement standard = 2,000 µg/L
  • Recommended preventive action limit = 400 µg/L

Wisconsin currently has groundwater standards for boron. DHS recommends no change to the proposed standards for boron.

Learn more

DHS' cycle 10 (boron) fact sheet has an overview of the recommended standards and steps to take if high levels are found in drinking water.

DHS' cycle 10 support document (pages 254-264 for boron) has a detailed summary of the scientific studies reviewed and rationale for the recommended standards.

Cobalt

Cobalt is a naturally occurring element that is used to produce alloys and color glass, ceramics and paints. High levels of cobalt can affect the lungs, heart, and skin and may affect the liver and kidneys and cause birth defects.

  • Recommended enforcement standard = 40 µg/L
  • Recommended preventive action limit = 4 µg/L

Wisconsin currently has groundwater standards for cobalt. DHS recommends lowering the preventive action limit for cobalt due to potential for cobalt to cause birth defects.

Learn more

DHS' cycle 10 (cobalt) fact sheet has an overview of the recommended standards and steps to take if high levels are found in drinking water.

DHS' cycle 10 support document (pages 293-304 for cobalt) has a detailed summary of the scientific studies reviewed and rationale for the recommended standards.

Molybdenum

Molybdenum is a natural mineral that is used in the production of cast iron and stainless steel, biofuels, solar panels, catalysts, lubricants, and pigments. Molybdenum may cause kidney and liver damage and affect reproduction and development.

  • Recommended enforcement standard = 60 µg/L
  • Recommended preventive action limit = 6 µg/L

Wisconsin currently has groundwater standards for molybdenum. DHS recommends updating the standards for molybdenum to based on new information from the Agency for Toxic Substances and Disease Registry (ATSDR).

Learn more

DHS' cycle 10 (molybdenum) fact sheet has an overview of the recommended standards and steps to take if high levels are found in drinking water.

DHS' cycle 10 support document (pages 265-273 for molybdenum) has a detailed summary of the scientific studies reviewed and rationale for the recommended standards.

Strontium

Strontium is a mineral that is commonly found in soil, bedrock, and groundwater. High levels of strontium can affect bone development in infants and young children who have a diet that is low in calcium and protein. Children who drink adequate amounts of formula or milk are not likely to develop these problems.

  • Recommended enforcement standard = 1,500 µg/L
  • Recommended preventive action limit = 150 µg/L

Wisconsin does not currently have groundwater standards for strontium. DHS' recommended standards are based on the health information established by the United States Environmental Protection Agency (EPA).

Learn more

DHS' cycle 10 (strontium) fact sheet has an overview of the recommended standards and steps to take if high levels are found in drinking water.

DHS' cycle 10 support document (pages 19-28 for strontium) has a detailed summary of the scientific studies reviewed and rationale for the recommended standards.

Pathogen Indicators

Escherichia coli

Escherichia coli (E. coli) is used to indicate the presence of fecal contamination in groundwater. Pathogens from fecal contamination can cause stomach flu like symptoms.

  • Recommended enforcement standard = 0 CFU
  • Recommended preventive action limit = 0 CFU

Wisconsin does not currently have groundwater standards for E. coli. DHS' recommended standards are based on the federal drinking water standard for E. coli.

Learn more

DHS' bacteria in private wells page has more information on addressing E. coli in private wells.

DHS' cycle 10 support document (pages 161-165 for E. coli) has a detailed summary of the scientific studies reviewed and rationale for the recommended standards.

Total Coliform

Total coliform bacteria are used to indicate issues with the integrity of the well. Wells with compromised integrity can be contaminated with pathogens.

  • Recommended enforcement standard = 0 CFU
  • Recommended preventive action limit = 0 CFU

Wisconsin currently has groundwater standards for total coliform. However, DNR has proposed transiting total coliform from a groundwater standard to an indicator parameter.

While DHS support DNR's proposal to change how total coliform is addressed in the regulatory process, DHS continues to recommend that private well owners take action if they detect total coliform in their water.

Learn more

DHS' bacteria in private wells page has more information on addressing total coliform bacteria in private wells.

Per- and Polyfluoroalkyl Substances (PFAS)

Perfluorooctane sulfonamide (PFOA)

Perfluorooctane sulfonamide (PFOA) is a type of per- and polyfluoroalkyl substances (PFAS). PFAS have been used in many products since the 1950s including food packaging, stain-resistant materials, and fire-fighting foam. PFOA can affect health - potential effects include increased cholesterol levels, decrease antibody response to certain vaccines, and reduced fertility in women.

  • Recommended enforcement standard = 20 ng/L for PFOA and 5 other PFAS
  • Recommended preventive action limit = 2 ng/L for PFOA and 5 other PFAS

Wisconsin does not currently have groundwater standards for PFOA. DHS recommends combined groundwater standards for PFOA, PFOS, perfluorooctane sulfonamide (FOSA), N-ethyl perfluorooctane sulfonamidoethanol (NEtFOSE), N-ethyl perfluorooctane sulfonamide (NEtFOSA), and N-ethyl perfluorooctane sulfonamidoacetic acid (NEtFOSAA) because they can co-occur in the environment, transform into each other in the body, and cause similar health effects. DHS' recommended standards are based on peer-reviewed scientific studies in research animals.

Learn more

DHS' cycle 10 (PFOA) fact sheet has an overview of the recommended standards and steps to take if high levels are found in drinking water.

DHS' cycle 10 support document (pages 166-189 for PFOA) has a detailed summary of the scientific studies reviewed and rationale for the recommended standards.

DHS' PFAS page has more information on exposure routes, health effects, evaluating risk, and reducing exposure.

DHS' cycle 11 page has more information on recommended standards for FOSA, NEtFOSE, NEtFOSA, and NEtFOSAA.

Perfluorooctane sulfonic acid (PFOS)

Perfluorooctane sulfonic acid (PFOS) is a type of per- and polyfluoroalkyl substances (PFAS). PFAS have been used in many products since the 1950s including food packaging, stain-resistant materials, and fire-fighting foam. PFOS can affect health - potential effects include increased cholesterol levels, decrease antibody response to certain vaccines, and reduced fertility in women.

  • Recommended enforcement standard = 20 ng/L for PFOS and 5 other PFAS
  • Recommended preventive action limit = 2 ng/L for PFOS and 5 other PFAS

Wisconsin does not currently have groundwater standards for PFOS. DHS recommends combined groundwater standards for PFOS, PFOA, perfluorooctane sulfonamide (FOSA), N-ethyl perfluorooctane sulfonamidoethanol (NEtFOSE), N-ethyl perfluorooctane sulfonamide (NEtFOSA), and N-ethyl perfluorooctane sulfonamidoacetic acid (NEtFOSAA) because they can co-occur in the environment, transform into each other in the body, and cause similar health effects. DHS' recommended standards are based on peer-reviewed scientific studies in research animals.

Learn more

DHS' cycle 10 (PFOS) fact sheet has an overview of the recommended standards and steps to take if high levels are found in drinking water.

DHS' cycle 10 support document (pages 190-216 for PFOS) has a detailed summary of the scientific studies reviewed and rationale for the recommended standards.

DHS' PFAS page has more information on exposure routes, health effects, evaluating risk, and reducing exposure.

DHS' cycle 11 page has more information on recommended standards for FOSA, NEtFOSE, NEtFOSA, and NEtFOSAA.

Pesticides and Herbicides

Aminomethylphosphonic acid

Aminomethylphosphonic acid (AMPA) is a major breakdown product of glyphosate. In the environment, glyphosate can be quickly turned into

AMPA. AMPA may affect the gastrointestinal and urinary tracts, damage the liver, and impact development.

  • Recommended enforcement standard = 10 mg/L
  • Recommended preventive action limit = 2 mg/L

Wisconsin does not currently have groundwater standards for AMPA. DHS' recommended standards are based on studies submitted to the United States Environmental Protection Agency (EPA).

Learn more

The Wisconsin Department of Agriculture, Trade, and Consumer Protection's (DATCP's) cycle 10 pesticide fact sheet has information on how glyphoaste is used and how it turns into AMPA in the environment.

DHS' cycle 10 (AMPA) fact sheet has an overview of the recommended standards and steps to take if high levels are found in drinking water.

DHS' cycle 10 support document (pages 143-153 for AMPA) has a detailed summary of the scientific studies reviewed and rationale for the recommended standards.

Clothianidin

Clothianidin is a pesticide used to control a variety of indoor and outdoor insects. Clothianidin may affect the liver, kidneys, and blood.

  • Recommended enforcement standard = 1,000 µg/L
  • Recommended preventive action limit = 200 µg/L

Wisconsin does not currently have groundwater standards for clothianidin. DHS' recommended standards are based on the health information established by the United States Environmental Protection Agency (EPA).

Learn more

The Wisconsin Department of Agriculture, Trade, and Consumer Protection's (DATCP's) cycle 10 pesticide fact sheet has information on how clothianidin is used and where it has been found in Wisconsin.

DHS' cycle 10 (clothianidin) fact sheet has an overview of the recommended standards and steps to take if high levels are found in drinking water.

DHS' cycle 10 support document (pages 61-69 for clothianidin) has a detailed summary of the scientific studies reviewed and rationale for the recommended standards.

Dacthal

Dacthal is a pesticide used to control a variety of weeds. In the environment, dacthal breaks down into monomethyl etrachloroterephthalic acid (MTP) and then tetrachloroterephthalic acid (TPA). While dacthal has been shown to impact the liver, lung, kidney, and thyroid and cause cancer in research animals, studies on MTP and TPA are limited.

  • Recommended enforcement standard = 70 µg/L for dacthal, MTP, and TPA
  • Recommended preventive action limit = 7 µg/L for dacthal, MTP, and TPA

Wisconsin currently has groundwater standards for dacthal but not MTP and TPA. DHS' recommended standards are based on the health information established by the United States Environmental Protection Agency (EPA).

Learn more

DATCP's cycle 10 pesticide fact sheet has information on how dacthal is used and where it has been found in Wisconsin.

DHS' cycle 10 (dacthal) fact sheet has an overview of the recommended standards and steps to take if high levels are found in drinking water.

DHS' cycle 10 support document (pages 108-128 for MTP and TPA) has a detailed summary of the scientific studies reviewed and rationale for the recommended standards.

Glyphosate

Glyphosate is an herbicide commonly used for weed control on agricultural fields, lawns, and gardens. Glyphoaste may affect the gastrointestinal system and impact development.

  • Recommended enforcement standard = 10 mg/L
  • Recommended preventive action limit = 1 mg/L

Wisconsin does not currently have groundwater standards for glyphosate. DHS' recommended standards are based on the health information established by the United States Environmental Protection Agency (EPA).

Learn more

DATCP's cycle 10 pesticide fact sheet has information on how glyphoaste is used and where it has been found in Wisconsin.

DHS' cycle 10 (dacthal) fact sheet has an overview of the recommended standards and steps to take if high levels are found in drinking water.

DHS' cycle 10 support document (pages 129-142 for glyphosate) has a detailed summary of the scientific studies reviewed and rationale for the recommended standards.

Imidacloprid

Imidacloprid is a pesticide that is used to control a variety of indoor and outdoor insects in agricultural fields, gardens, and pet collars. Imidacloprid may cause thyroid, neurological, reproductive, and glucose regulation problems.

  • Recommended enforcement standard = 0.2 µg/L
  • Recommended preventive action limit = 0.02 µg/L

Wisconsin does not currently have groundwater standards for imidacloprid. DHS' recommended standards are based on peer-reviewed research studies in research animals.

Learn more

DATCP's cycle 10 pesticide fact sheet has information on how imidacloprid is used and where it has been found in Wisconsin.

DHS' cycle 10 (imidacloprid) fact sheet has an overview of the recommended standards and steps to take if high levels are found in drinking water.

DHS' cycle 10 support document (pages 39-60 for imidacloprid) has a detailed summary of the scientific studies reviewed and rationale for the recommended standards.

Isoxaflutole and isoxaflutole diketonitrile

Isoxaflutole is a herbicide used to control weeds in field corn and soybeans. In the body and the environment, isoxaflutole quickly breaks down into isoxaflutole diketonitrile (DKN). Isoxaflutole may cause liver, thyroid, eye, nerve, and muscle problems and tumor formation.

  • Recommended enforcement standard = 3 µg/L for isoxaflutole and isoxaflutole DKN
  • Recommended preventive action limit = 0.3 µg/L for isoxaflutole and isoxaflutole DKN

Wisconsin does not currently have groundwater standards for isoxaflutole and isoxaflutole DKN. DHS' recommended standards are based on health information from the United States Environmental Protection Agency (EPA). DHS recommends a combined enforcement standard for isoxaflutole and isoxaflutole DKN because isoxaflutole breaks down quickly into isoxaflutole DKN in the body.

Learn more

DATCP's cycle 10 pesticide fact sheet has information on how isoxaflutole is used and where it has been found in Wisconsin.

DHS' cycle 10 (isoxaflutole) fact sheet has an overview of the recommended standards and steps to take if high levels are found in drinking water.

DHS' cycle 10 support document (pages 70-88 for isoxaflutole and isoxaflutole DKN) has a detailed summary of the scientific studies reviewed and rationale for the recommended standards.

Sulfentrazone

Sulfentrazone is a herbicide used to control weeds on many plants including agricultural crops, golf courses, seedling nurseries, and landscaping. Sulfentrazone may affect reproduction and development.

  • Recommended enforcement standard = 1,000 µg/L
  • Recommended preventive action limit = 100 µg/L

Wisconsin does not currently have groundwater standards for sulfentrazone. DHS' recommended standards are based on health information from the United States Environmental Protection Agency (EPA).

Learn more

DATCP's cycle 10 pesticide fact sheet has information on how sulfentrazone is used and where it has been found in Wisconsin.

DHS' cycle 10 (sulfentrazone) fact sheet has an overview of the recommended standards and steps to take if high levels are found in drinking water.

DHS' cycle 10 support document (pages 154-160 for sulfentrazone) has a detailed summary of the scientific studies reviewed and rationale for the recommended standards.

Thiamethoxam

Thiamethoxam is a pesticide used for indoor and outdoor pests on agricultural fields, gardens, pets, and in homes. Thiamethoxam can affect the blood, liver, and reproduction.

  • Recommended enforcement standard = 120 µg/L
  • Recommended preventive action limit = 12 µg/L

Wisconsin does not currently have groundwater standards for thiamethoxam. DHS' recommended standards are based on health information from the United States Environmental Protection Agency (EPA).

Learn more

DATCP's cycle 10 pesticide fact sheet has information on how thiamethoxam is used and where it has been found in Wisconsin.

DHS' cycle 10 (thiamethoxam) fact sheet has an overview of the recommended standards and steps to take if high levels are found in drinking water.

DHS' cycle 10 support document (pages 29-38 or thiamethoxam) has a detailed summary of the scientific studies reviewed and rationale for the recommended standards.

Thiencarbazone-methyl

Thiencarbazone-methyl is a pesticide used for indoor and outdoor pests used on agricultural fields, gardens, pets, and in homes. Thiencarbazone-methyl may affect the kidney, bladder, and urinary tract.

  • Recommended enforcement standard = 10 mg/L
  • Recommended preventive action limit = 2 mg/L

Wisconsin does not currently have groundwater standards for thiencarbazone-methyl. DHS' recommended standards are based on health information from the United States Environmental Protection Agency (EPA).

Learn more

DATCP's cycle 10 pesticide fact sheet has information on how thiencarbazone-methyl is used and where it has been found in Wisconsin.

DHS' cycle 10 (thiencarbazone-methyl) fact sheet has an overview of the recommended standards and steps to take if high levels are found in drinking water.

DHS' cycle 10 support document (pages 101-107 for thiencarbazone-methyl) has a detailed summary of the scientific studies reviewed and rationale for the recommended standards.

Volatile organic compounds (VOCs)

1,1-Dichloroethane

1,1-Dichloroethane (1,1-DCA) is a volatile organic compound that is used to make other chemicals. 1,2-Dichlorethane may affect the kidneys and liver, delay development, and may cause cancer.

  • Recommended enforcement standard = 850 µg/L
  • Recommended preventive action limit = 85 µg/L

Wisconsin currently has groundwater standards for 1,2-dichlorethane. The current standard is based on a peer-reviewed study in research animals.

Learn more

DHS' cycle 10 (1,1-dichloroethane) fact sheet has an overview of the recommended standards and steps to take if high levels are found in drinking water.

DHS' cycle 10 support document (pages 247-253 for 1,2-dichlorethane) has a detailed summary of the scientific studies reviewed and rationale for the recommended standards.

Tetrachloroethylene (PCE)

Tetrachloroethylene (PCE) is human-made chemical that does not occur naturally in the environment. It is used for dry cleaning, metalworking, textile processing, and fluorocarbons manufacturing.

  • Recommended enforcement standard = 20 µg/L
  • Recommended preventive action limit = 2 µg/L

Wisconsin currently has groundwater standards for PCE. DHS recommends increasing the standards for PCE based on recent health information from the United States Environmental Protection Agency (EPA).

Learn more

DHS' cycle 10 (PCE) fact sheet has an overview of the recommended standards and steps to take if high levels are found in drinking water.

DHS' cycle 10 support document (pages 227-235 for PCE) has a detailed summary of the scientific studies reviewed and rationale for the recommended standards.

Trichloroethylene (TCE)

Trichloroethylene (TCE) is human-made chemical that does not occur naturally in the environment. It is used for dry cleaning, metalworking, textile processing, and fluorocarbons manufacturing.

  • Recommended enforcement standard = 0.5 µg/L
  • Recommended preventive action limit = 0.05 µg/L

Wisconsin currently has groundwater standards for TCE. DHS recommends decreasing the standards for TCE based on recent health information from the United States Environmental Protection Agency (EPA).

Learn more

DHS' cycle 10 (TCE) fact sheet has an overview of the recommended standards and steps to take if high levels are found in drinking water.

DHS' cycle 10 support document (pages 217-226 for TCE) has a detailed summary of the scientific studies reviewed and rationale for the recommended standards.

1,2,3-Trichloropropane

1,2,3-Trichloropropane (1,2,3-TCP) is an organic chemical that is used to make other chemicals. 1,2,3-TCP may cause tumors.

  • Recommended enforcement standard = 0.3 ng/L
  • Recommended preventive action limit = 0.03 ng/L

Wisconsin currently has groundwater standards for 1,2,3-TCP. DHS recommends decreasing the standards for 1,2,3-TCP based on recent health information from the United States Environmental Protection Agency (EPA).

Learn more

DHS' cycle 10 (1,2,3-TCP) fact sheet has an overview of the recommended standards and steps to take if high levels are found in drinking water.

DHS' cycle 10 support document (pages 236-246 for 1,2,3-TCP) has a detailed summary of the scientific studies reviewed and rationale for the recommended standards.

 

DHS' recommended standards are reported as mg/L (milligrams per liter), µg/L (micrograms per liter), ng/L (nanograms per liter), or CFU (colony forming units). Additional information on these unit measurements can be found on our chemicals page.

Questions? Can't find what you're looking for? Contact us!

Last Revised: July 8, 2022