Door County Private Well Monitoring Program

Past Testing Results

The common contaminants that are tested for in the study have been bacteria in the form of Total Coliform and E. coli and Nitrate. The following table summarizes the results from 2019 - 2021. The numbers displayed show the percentage of Door County wells indicating various levels of contaminants compared to Wisconsin averages.

Water Quality Standard 
(Level Detected)
Spring 2022 
(260 wells)
2021
(217 wells)
2020 
(295 wells)
2019 
(148 wells)
Wisconsin Average
Total Coliform (0 MPN/100 ml)90%
76%
86%
84%
17%
(>0 MPN/100 ml)
Total Coliform (1-10 MPN/100 ml)6%
14%
9%10%
Total Coliform (10-100 MPN/100 ml)3%
6%
3%4%
Total Coliform (>100 MPN/100 ml)1%
3%
1%1%
E.coli (0 MPN/100 ml)99%
98%
99%100%5%
(>0 MPN/100 ml)
E.coli (1-10 MPN/100 ml)<1%
1%
1%0%
E.coli (10-100 MPN/100 ml)0%
<1%
0%0%
E.coli (>100 MPN/100ml)0%
0%
0%0%
Nitrate (0 mg/L)80%
75%
72%71%10%
(>10 mg/L)
Nitrate (2-5 mg/L)16%
11%
16%
16%
Nitrate (5-10 mg/L)(>10 mg/L)4%
12%
12%
11%
Nitrate (>10 mg/L)0%
2%
<1%
2%
Arsenic (<2 µg/L)88%
89%
90%
99%
4%
(>10 µg/L)
Arsenic (2-5 µg/L)11%
9%
6%
1%
Arsenic (5-10 µg/L)1%
1%
3%
0%
Arsenic (>10 µg/L)0%

1%
<1%
0%


2022 Spring UW-Oshkosh Presentation of the Door County Well Monitoring Program (pdf)

2022 Spring UW-Oshkosh Recorded Presentation of the Door County Well Monitoring Program


2021 UW-Oshkosh Presentation of the Door County Well Monitoring Program (pdf)


2020 UW-Oshkosh Presentation of the Door County Well Monitoring Program (pdf)

2020 UW-Oshkosh Door County Well Monitoring Final Report (pdf)


2019 UW-Oshkosh Presentation of the Door County Well Monitoring Program (pdf)


2022 Fall Private Well Monitoring Program

For a fourth year, UW-Oshkosh will be conducting a fall private well groundwater study in Door County. This is a collaborative effort between the Door County Public Health and Soil and Water Conservation Departments with a goal of providing education to private well owners about the quality of their drinking water, as well as the importance of routine testing. A secondary goal is to build a long-term database of groundwater quality in Door County to allow resource professionals to make informed decisions in the protection of our fragile groundwater resources. 

If you are a private well owner, please consider participating to learn more about the drinking water that you and your neighbors rely on, as well as to help contribute to our knowledge of the resource.

To participate, follow the easty steps outlined below:

1.  RSVP using the linkor QR code by September 12, 2022: https://uwo.sh/doorco-wells-fall22

  • Total Coliform/E. coli/Nitrate for $30*
  • Optional: Arsenic & cummulative tests for an additional $25

Sampling kits will not be mailed until payment has been received by UW-Oshkosh.

2.  Attend a virtual forum to learn how to sample, receive sampling kit in mail.

3.  Collect well water sample on Ocotober 7th or 8th and submit it to a designated drop-off location:

  • North Highway Department Shop, 10363 Highway 57, Sister Bay
  • ADRC of Door County, 916 N 14th Avenue, Sturgeon Bay
  • South Highway Department Shop, 1729 County RD DK, Brussels
  • Washington Island - Please contact WICHP at 920-847-2108 or wisch77@gmail.com to make drop off arrangements

4.  Receive results & countywide summary of the study.


2022 Fall QR Sign-up CodeCollection Site Map