Data & Methodology — Adams County

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

Contaminant Data — All Analytes

187 well testing events on record, covering 19 analytes. Data spans 1945 to 2023.

Contaminant Samples Years Detection Rate Distribution LowModHigh vs. Limit vs. WI Avg
Manganese 36 1945–2023 61%
120% of limit ~ typical
Nitrate 175 1964–2014 98%
34% of limit ↑ 105% above
Iron 35 1953–2023 80%
17% of limit ↓ 93% below
Uranium 5 1980–2023 80%
1% of limit ↓ 62% below
Sulfate 42 1945–2023 100%
4% of limit ↓ 38% below
PFOS 5 2022 20%
9% of limit ↓ 85% below
PFOA 5 2022 40%
20% of limit ↑ 31% above
PFNA 5 2022 40%
3% of limit ~ typical
PFHxS 5 2022 40%
2% of limit ↓ 82% below
Nitrite 168 1966–2014 18%
1% of limit ~ typical
Lead 20 1973–2023 10%
0% of limit ↓ 100% below
HFPO-DA (GenX) 5 2022 0%
— —
Fluoride 23 1945–2023 83%
2% of limit ↓ 47% below
Chloride 180 1945–2023 98%
2% of limit ↓ 54% below
Arsenic 20 1973–2023 75%
10% of limit ↓ 35% below
Hardness 43 1945–2023 100%
— ↓ 39% below
Sodium 172 1966–2023 100%
— ↓ 83% below
pH 183 1945–2023 100%
— ~ typical
PFBS 5 2022 60%
— ↓ 44% 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 Adams County

Of the 20 arsenic tests on record for Adams County (1973–2023), 25% found none, and half were below 1 µg/L.

Of the 180 chloride tests on record for Adams County (1945–2023), 2% found none, and half were below 4.45 mg/L.

Of the 23 fluoride tests on record for Adams County (1945–2023), 17% found none, and half were below 100 µg/L.

Of the 35 iron tests on record for Adams County (1953–2023), 20% found none, and half were below 30 µg/L.

Of the 20 lead tests on record for Adams County (1973–2023), 90% found none.

Of the 36 manganese tests on record for Adams County (1945–2023), 39% found none, and half were below 25 µg/L.

Of the 175 nitrate tests on record for Adams County (1964–2014), 2% found none, and half were below 3.4 mg/L.

Of the 42 sulfate tests on record for Adams County (1945–2023), 0% found none, and half were below 11 mg/L.

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Data Coverage & Gaps

Well-sampled analytes (15+ samples)

  • Manganese 36 samples
  • Nitrate 175 samples
  • Iron 35 samples
  • Sulfate 42 samples
  • Nitrite 168 samples
  • Lead 20 samples
  • Fluoride 23 samples
  • Chloride 180 samples
  • Arsenic 20 samples
  • Hardness 43 samples
  • Sodium 172 samples
  • pH 183 samples

Limited data (<15 samples) — interpret with caution

  • Uranium 5 samples
  • PFOS 5 samples
  • PFOA 5 samples
  • PFNA 5 samples
  • PFHxS 5 samples
  • HFPO-DA (GenX) 5 samples
  • PFBS 5 samples

CDC Health Outcome Correlations

Where contaminants detected in Adams County have established associations with specific health outcomes, we cross-reference CDC PLACES county-level prevalence data. This is a contextual signal, not a causal claim.

Contaminant Associated Condition Adams County Prevalence WI Average Source Year
Nitrate Cancer prevalence 9.4% 7.0% 2020

Source: CDC PLACES county-level estimates. Raw data: Download Adams County CDC PLACES data →

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

Full methodology →