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 - 2022. The numbers displayed show the percentage of Door County wells indicating various levels of contaminants compared to Wisconsin averages.

Water Quality Standard 
(Level Detected)
Fall 2022
(196 wells)
Spring 2022 
(260 wells)
2021
(217 wells)
2020 
(295 wells)
2019 
(148 wells)
Wisconsin Average
Total Coliform (0 MPN/100 ml)92%90%
76%
86%
84%
17%
(>0 MPN/ 100 ml)
Total Coliform (1-10 MPN/100 ml)6%6%
14%
9%10%
Total Coliform (10-100 MPN/100 ml)2%3%
6%
3%4%
Total Coliform (>100 MPN/100 ml)1%1%
3%
1%1%
E.coli (0 MPN/100 ml)100%99%
98%
99%100%5%
(>0 MPN/ 100 ml)
E.coli (1-10 MPN/100 ml)0%<1%
1%
1%0%
E.coli (10-100 MPN/100 ml)0%0%
<1%
0%0%
E.coli (>100 MPN/100ml)0%0%
0%
0%0%
Nitrate (0 mg/L)74%80%
75%
72%71%10%
(>10 mg/L)
Nitrate (2-5 mg/L)18%16%
11%
16%
16%
Nitrate (5-10 mg/L)(>10 mg/L)7%4%
12%
12%
11%
Nitrate (>10 mg/L)1%0%
2%
<1%
2%
Arsenic (<2 µg/L)92%88%
89%
90%
99%
4%
(>10 µg/L)
Arsenic (2-5 µg/L)7%11%
9%
6%
1%
Arsenic (5-10 µg/L)1%1%
1%
3%
0%
Arsenic (>10 µg/L)0%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)