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EPA in Wisconsin

Juneau County Groundwater Screening Investigation

February 2019 Update

EPA released the inspection report in August 2018.  EPA is releasing this memo which provides further analysis of data collected as part of the Juneau County groundwater investigation.

October 2018 Update

As part of the April 30 through May 3, 2018 inspection, EPA took samples that were analyzed for different isotopes of nitrogen and oxygen.   These results were included in the August 30, 2018 inspection report attached below.  The University of Nebraska Water Science Laboratory recently completed a report: Nitrate-N Isotope Results and Interpretation.

In October of 2017, EPA did an initial sampling of groundwater and surface water in and west of Petenwell Lake in northeast Juneau County.  The inspection report 2017 Northeast Juneau County Groundwater and Surface Water Sampling Investigation and data from that sampling inspection is posted in the documents section below. 

August 2018 Update

EPA has finalized its Sampling Inspection Report related to the results of May 2018 groundwater testing conducted in Juneau County. EPA’s tests – and others conducted by the county health department – found elevated levels of nitrates. The Sampling Inspection Report summarizes EPA’s groundwater screening investigation with descriptions of sampling preparation and methods and discussions of sampling results including maps. Region 5 continues to work with Wisconsin Department of Natural Resources to determine appropriate next steps.


From April 30 through May 3, 2018, EPA sampled groundwater west of Petenwell Lake in northeast Juneau County after receiving complaints and information from citizens in the area regarding private drinking-water well contamination.

EPA collected groundwater samples at 41 temporary boring locations and 5 private drinking water wells. The samples were analyzed for:
  • nutrients
  • anions
  • total metals
  • nitrate isotopes

Note that not all samples were analyzed for all parameters.

EPA used temporary or “point-in-time” groundwater sampling techniques with the goal of characterizing the nature and extent of pollutants in groundwater. This information can be used to identify potential sources of groundwater pollutants and potential impacts to drinking water sources.

The borings were located in a grid network designed to characterize groundwater conditions upgradient and downgradient of potential sources of well contamination.  Samples were collected at two depths to better characterize the extent of potential nitrate contamination in the aquifer.

EPA continues to evaluate data collected during the April 30 to May 3, 2018, sampling event.  EPA will coordinate further with Wisconsin DNR to determine the appropriate next steps to protect public health.


EPA Laboratory and Field Screening Data for Juneau County Groundwater (ZIP)(21 pp, 6 MB, June 28, 2018)

Juneau County Findings Memo

EPA Sampling Inspection Report, April 30- May 3, 2018

2017 Northeast Juneau County Groundwater and Surface Water Sampling Investigation 

University of Nebraska Water Science Laboratory reports: Nitrate-N Isotope Results and Interpretation and Quality Control Summary Report
Nitrate-N Isotope Analysis