Data & Methodology — Goodhue County

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

Contaminant Data — All Analytes

348 well testing events on record, covering 22 analytes. Data spans 1943 to 2025.

Contaminant Samples Years Detection Rate Distribution LowModHigh vs. Limit vs. MN Avg
Iron 239 1963–2025 86%
40% of limit ↓ 94% below
Manganese 228 1963–2025 78%
71% of limit ↓ 86% below
PFOA municipal 32 2024–2025 62%
65% of limit ↓ 85% below
PFOS municipal 21 2024–2025 38%
99% of limit ↓ 51% below
Nitrate 284 1963–2018 87%
11% of limit ↓ 53% below
Lead 56 1974–2025 25%
10% of limit ↓ 77% below
Arsenic 55 1974–2025 31%
4% of limit ↓ 95% below
Chloride 256 1963–2025 100%
2% of limit ↓ 71% below
Fluoride 218 1963–2025 77%
5% of limit ↓ 28% below
HFPO-DA (GenX) municipal 13 2024–2025 0%
— —
Nitrite 246 1974–2018 48%
0% of limit ↓ 87% below
PFHxS municipal 16 2024–2025 44%
11% of limit ↓ 86% below
PFNA municipal 13 2024–2025 0%
— —
Radon 3 1996 100%
7% of limit ↓ 86% below
Sulfate 233 1963–2025 100%
9% of limit ↓ 52% below
Uranium 10 1980–2018 40%
2% of limit ↓ 50% below
Total Coliform 2 2007–2018 33%
— ~ typical
Sodium 233 1963–2025 100%
— ↓ 87% below
pH 180 1963–2018 100%
— ~ typical
PFBS municipal 23 2024–2025 61%
— ↑ 37% above
Hardness 100 1963–2018 100%
— ~ typical
E. coli 2 2007–2018 0%
— —

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 Goodhue County

Of the 55 arsenic tests on record for Goodhue County (1974–2025), 69% found none.

Of the 256 chloride tests on record for Goodhue County (1963–2025), 0% found none, and half were below 5.57 mg/L.

Of the 218 fluoride tests on record for Goodhue County (1963–2025), 23% found none, and half were below 180 µg/L.

Of the 239 iron tests on record for Goodhue County (1963–2025), 14% found none, and half were below 50 µg/L.

Of the 56 lead tests on record for Goodhue County (1974–2025), 75% found none.

Of the 228 manganese tests on record for Goodhue County (1963–2025), 22% found none, and half were below 20 µg/L.

Of the 284 nitrate tests on record for Goodhue County (1963–2018), 13% found none, and half were below 443 µg/L.

Of the 23 pfoa tests on record for Goodhue County (2024–2025), 13% found none, and half were below 2 ng/L.

Of the 233 sulfate tests on record for Goodhue County (1963–2025), 0% found none, and half were below 22.7 mg/L.

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Data Coverage & Gaps

Well-sampled analytes (15+ samples)

  • Iron 239 samples
  • Manganese 228 samples
  • PFOA 32 samples
  • PFOS 21 samples
  • Nitrate 284 samples
  • Lead 56 samples
  • Arsenic 55 samples
  • Chloride 256 samples
  • Fluoride 218 samples
  • Nitrite 246 samples
  • PFHxS 16 samples
  • Sulfate 233 samples
  • Sodium 233 samples
  • pH 180 samples
  • PFBS 23 samples
  • Hardness 100 samples

Limited data (<15 samples) — interpret with caution

  • HFPO-DA (GenX) 13 samples
  • PFNA 13 samples
  • Radon 3 samples
  • Uranium 10 samples
  • Total Coliform 2 samples
  • E. coli 2 samples

Public vs. Private Water in Goodhue County

91 Active public water systems
44,002 Residents on public water
33% Households on private wells

Public water systems in Goodhue 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 Goodhue 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 Goodhue County Prevalence MN Average Source Year
Arsenic Cancer prevalence 8.0% 7.0% 2020
Arsenic Kidney disease rate 3.1% 2.9% 2020
Lead Heart disease rate 7.2% 6.6% 2020

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