Data & Methodology — Le Sueur County

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

Contaminant Data — All Analytes

58 well testing events on record, covering 19 analytes. Data spans 1955 to 2022.

Contaminant Samples Years Detection Rate Distribution LowModHigh vs. Limit vs. MN Avg
PFOA municipal 21 2023–2025 62%
950% of limit ↑ 121% above
Iron 35 1960–2005 71%
403% of limit ↓ 44% below
Manganese 34 1960–2000 76%
182% of limit ↓ 63% below
PFOS municipal 18 2023–2025 56%
412% of limit ↑ 105% above
PFHxS municipal 15 2023–2025 47%
190% of limit ↑ 138% above
Nitrate 39 1960–2005 87%
10% of limit ↓ 59% below
Arsenic 26 1980–2000 46%
46% of limit ↓ 46% below
Chloride 38 1960–2005 100%
1% of limit ↓ 92% below
Fluoride 37 1960–2000 95%
8% of limit ~ typical
HFPO-DA (GenX) municipal 8 2023–2025 0%
— —
Lead 26 1980–2000 8%
4% of limit ↓ 90% below
Nitrite 19 1980–2000 11%
4% of limit ↑ 232% above
PFNA municipal 8 2023–2025 0%
— —
Sulfate 37 1960–2000 100%
4% of limit ↓ 79% below
Uranium 12 1980–2000 100%
7% of limit ↑ 70% above
Sodium 34 1960–2000 100%
— ↓ 32% below
pH 33 1960–2000 100%
— ~ typical
PFBS municipal 17 2023–2025 53%
— ↑ 50% above
Hardness 19 1960–2000 100%
— ~ typical

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 Le Sueur County

Of the 26 arsenic tests on record for Le Sueur County (1980–2000), 54% found none.

Of the 38 chloride tests on record for Le Sueur County (1960–2005), 0% found none, and half were below 1.46 mg/L.

Of the 37 fluoride tests on record for Le Sueur County (1960–2000), 5% found none, and half were below 300 µg/L.

Of the 35 iron tests on record for Le Sueur County (1960–2005), 29% found none, and half were below 484 µg/L.

Of the 26 lead tests on record for Le Sueur County (1980–2000), 92% found none.

Of the 34 manganese tests on record for Le Sueur County (1960–2000), 24% found none, and half were below 36.5 µg/L.

Of the 39 nitrate tests on record for Le Sueur County (1960–2005), 13% found none, and half were below 290 µg/L.

Of the 37 sulfate tests on record for Le Sueur County (1960–2000), 0% found none, and half were below 10 mg/L.

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Data Coverage & Gaps

Well-sampled analytes (15+ samples)

  • PFOA 21 samples
  • Iron 35 samples
  • Manganese 34 samples
  • PFOS 18 samples
  • PFHxS 15 samples
  • Nitrate 39 samples
  • Arsenic 26 samples
  • Chloride 38 samples
  • Fluoride 37 samples
  • Lead 26 samples
  • Nitrite 19 samples
  • Sulfate 37 samples
  • Sodium 34 samples
  • pH 33 samples
  • PFBS 17 samples
  • Hardness 19 samples

Limited data (<15 samples) — interpret with caution

  • Uranium 12 samples

Public vs. Private Water in Le Sueur County

50 Active public water systems
28,355 Residents on public water
40% Households on private wells

Public water systems in Le Sueur 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 Le Sueur 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 Le Sueur County Prevalence MN Average Source Year
Arsenic Cancer prevalence 7.6% 7.0% 2020
Arsenic Kidney disease rate 2.4% 2.9% 2020
Lead Heart disease rate 6.8% 6.6% 2020

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