Data & Methodology — Jackson County

Full contaminant data, sample history, and sourcing for Jackson County. For readers who want to go beyond the summary.

Contaminant Data — All Analytes

44 well testing events on record, covering 19 analytes. Data spans 1935 to 2023.

Contaminant Samples Years Detection Rate Distribution LowModHigh vs. Limit vs. WI Avg
Iron 32 1935–1983 100%
133% of limit ↓ 44% below
Manganese 32 1935–1983 94%
140% of limit ~ typical
Arsenic 1 1980 100%
20% of limit ↑ 29% above
Chloride 29 1935–1983 100%
1% of limit ↓ 75% below
Fluoride 21 1945–1983 76%
5% of limit ~ typical
HFPO-DA (GenX) municipal 14 2022–2023 0%
— —
Lead 5 1976–1980 0%
— —
Nitrate 26 1935–1983 88%
1% of limit ↓ 92% below
Nitrite 12 1935–1983 75%
0% of limit ↓ 69% below
PFHxS municipal 14 2022–2023 7%
2% of limit ↓ 86% below
PFNA municipal 14 2022–2023 0%
— —
PFOA municipal 14 2022–2023 7%
15% of limit ~ typical
PFOS municipal 14 2022–2023 7%
7% of limit ↓ 89% below
Sulfate 30 1935–1983 97%
4% of limit ↓ 38% below
Uranium 1 1980 0%
— —
Hardness 32 1935–1983 100%
— ↓ 85% below
PFBS municipal 14 2022–2023 0%
— —
pH 31 1945–1983 100%
— ~ typical
Sodium 18 1965–1983 100%
— ↓ 68% below

Distribution shows the share of samples in each concentration band relative to the EPA Maximum Contaminant Level (MCL): Low = below half the MCL, Moderate = between half and the MCL, High = above the MCL. Analytes without an MCL (e.g. sodium, pH) show — in the limit columns. State average is based on county median values across WI.

Compare your result with Jackson County

Of the 29 chloride tests on record for Jackson County (1935–1983), 0% found none, and half were below 2.8 mg/L.

Of the 21 fluoride tests on record for Jackson County (1945–1983), 24% found none, and half were below 200 µg/L.

Of the 32 iron tests on record for Jackson County (1935–1983), 0% found none, and half were below 400 µg/L.

Of the 32 manganese tests on record for Jackson County (1935–1983), 6% found none, and half were below 65 µg/L.

Of the 26 nitrate tests on record for Jackson County (1935–1983), 12% found none, and half were below 75 µg/L.

Of the 30 sulfate tests on record for Jackson County (1935–1983), 3% found none, and half were below 11 mg/L.

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Data Coverage & Gaps

Well-sampled analytes (15+ samples)

  • Iron 32 samples
  • Manganese 32 samples
  • Chloride 29 samples
  • Fluoride 21 samples
  • Nitrate 26 samples
  • Sulfate 30 samples
  • Hardness 32 samples
  • pH 31 samples
  • Sodium 18 samples

Limited data (<15 samples) — interpret with caution

  • Arsenic 1 sample
  • HFPO-DA (GenX) 14 samples
  • Lead 5 samples
  • Nitrite 12 samples
  • PFHxS 14 samples
  • PFNA 14 samples
  • PFOA 14 samples
  • PFOS 14 samples
  • Uranium 1 sample
  • PFBS 14 samples

Data Sources

This report aggregates data from the following public databases:

Methodology

Raw records are downloaded from the Water Quality Portal and normalized to µg/L (ppb). Records are deduplicated by sample ID and date, and certified outliers are excluded. Analyte names are mapped to EPA canonical forms. Detection rates, distribution bands, and MCL comparisons are computed from the normalized dataset.

Distribution bands use the EPA Maximum Contaminant Level as the threshold: concentrations below 50% of the MCL are classed as Low, between 50% and 100% as Moderate, and above 100% as High. For analytes without an MCL (sodium, hardness, pH), distribution is not computed.

State comparison uses the median of county median values across all counties in WI with at least one sample for that analyte.

Last updated: 2026-07-15

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