Data & Methodology — Wadena County

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

Contaminant Data — All Analytes

637 well testing events on record, covering 18 analytes. Data spans 1964 to 2024.

Contaminant Samples Years Detection Rate Distribution LowModHigh vs. Limit vs. MN Avg
Iron 561 1964–2025 92%
467% of limit ↓ 35% below
Manganese 242 1964–2025 80%
280% of limit ↓ 43% below
PFOS municipal 12 2024–2025 50%
262% of limit ↑ 31% above
PFOA municipal 16 2006–2025 56%
375% of limit ~ typical
PFHxS municipal 8 2024 75%
75% of limit ~ typical
Nitrate 36 1964–2007 67%
10% of limit ↓ 57% below
Arsenic 151 1995–2025 66%
18% of limit ↓ 79% below
Lead 151 1995–2025 10%
1% of limit ↓ 97% below
Sulfate 269 1964–2025 90%
3% of limit ↓ 82% below
Chloride 616 1964–2025 96%
4% of limit ↓ 43% below
Fluoride 212 1964–2025 87%
2% of limit ↓ 64% below
HFPO-DA (GenX) municipal 9 2022–2025 0%
— —
Nitrite 4 1998 0%
— —
PFNA municipal 10 2006–2025 0%
— —
Hardness 84 1964–1981 100%
— ~ typical
PFBS municipal 6 2024 67%
— ~ typical
pH 391 1964–2013 100%
— ~ typical
Sodium 252 1964–2025 100%
— ↓ 85% 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 MN.

Compare your result with Wadena County

Of the 151 arsenic tests on record for Wadena County (1995–2025), 34% found none, and half were below 0.56 µg/L.

Of the 616 chloride tests on record for Wadena County (1964–2025), 4% found none, and half were below 10 mg/L.

Of the 212 fluoride tests on record for Wadena County (1964–2025), 13% found none, and half were below 100 µg/L.

Of the 561 iron tests on record for Wadena County (1964–2025), 8% found none, and half were below 1.17 mg/L.

Of the 151 lead tests on record for Wadena County (1995–2025), 90% found none.

Of the 242 manganese tests on record for Wadena County (1964–2025), 20% found none, and half were below 90.5 µg/L.

Of the 36 nitrate tests on record for Wadena County (1964–2007), 33% found none.

Of the 269 sulfate tests on record for Wadena County (1964–2025), 10% found none, and half were below 6.83 mg/L.

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Data Coverage & Gaps

Well-sampled analytes (15+ samples)

  • Iron 561 samples
  • Manganese 242 samples
  • PFOA 16 samples
  • Nitrate 36 samples
  • Arsenic 151 samples
  • Lead 151 samples
  • Sulfate 269 samples
  • Chloride 616 samples
  • Fluoride 212 samples
  • Hardness 84 samples
  • pH 391 samples
  • Sodium 252 samples

Limited data (<15 samples) — interpret with caution

  • PFOS 12 samples
  • PFHxS 8 samples
  • HFPO-DA (GenX) 9 samples
  • Nitrite 4 samples
  • PFNA 10 samples
  • PFBS 6 samples

Public vs. Private Water in Wadena County

44 Active public water systems
8,366 Residents on public water
45% Households on private wells

Public water systems in Wadena County are regulated by the EPA and must test and report contaminant levels. Private well owners are responsible for their own testing — there is no routine monitoring of private wells by any government agency.

CDC Health Outcome Correlations

Where contaminants detected in Wadena 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 Wadena County Prevalence MN Average Source Year
Arsenic Cancer prevalence 8.4% 7.0% 2020
Arsenic Kidney disease rate 2.8% 2.9% 2020
Lead Heart disease rate 8.7% 6.6% 2020

Source: CDC PLACES county-level estimates. Raw data: Download Wadena 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 MN with at least one sample for that analyte.

Last updated: 2026-08-04

Full methodology →