Data & Methodology — Houston County

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

Contaminant Data — All Analytes

180 well testing events on record, covering 20 analytes. Data spans 1958 to 2024.

Contaminant Samples Years Detection Rate Distribution LowModHigh vs. Limit vs. MN Avg
PFOS municipal 9 2025 78%
22% of limit —
Iron 135 1963–2017 50%
128% of limit ↓ 77% below
PFOA municipal 10 2025 80%
64% of limit ↑ 1620% above
Manganese 61 1963–2016 61%
17% of limit ↓ 95% below
Arsenic 121 1973–2016 26%
2% of limit ↓ 97% below
Chloride 167 1963–2025 87%
2% of limit ↓ 87% below
Fluoride 135 1963–2021 99%
3% of limit ↓ 68% below
HFPO-DA (GenX) municipal 2 2025 0%
— —
Lead 121 1973–2016 45%
1% of limit ↓ 98% below
Nitrate 76 1963–2015 96%
8% of limit ↓ 59% below
Nitrite 65 1991–2015 6%
0% of limit ↓ 94% below
PFHxS municipal 6 2025 67%
50% of limit —
PFNA municipal 3 2025 33%
25% of limit —
Radon 1 2014 100%
86% of limit ~ typical
Sulfate 136 1963–2021 99%
6% of limit ↓ 74% below
Uranium 63 2014–2015 83%
1% of limit ↓ 61% below
Sodium 133 1963–2017 89%
— ↓ 94% below
pH 15 1963–2021 100%
— ~ typical
PFBS municipal 6 2025 67%
— —
Hardness 10 1963–2014 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.

Data Coverage & Gaps

Well-sampled analytes (15+ samples)

  • Iron 135 samples
  • Manganese 61 samples
  • Arsenic 121 samples
  • Chloride 167 samples
  • Fluoride 135 samples
  • Lead 121 samples
  • Nitrate 76 samples
  • Nitrite 65 samples
  • Sulfate 136 samples
  • Uranium 63 samples
  • Sodium 133 samples
  • pH 15 samples

Limited data (<15 samples) — interpret with caution

  • PFOS 9 samples
  • PFOA 10 samples
  • PFHxS 6 samples
  • PFNA 3 samples
  • Radon 1 sample
  • PFBS 6 samples
  • Hardness 10 samples

Public vs. Private Water in Houston County

46 Active public water systems
14,525 Residents on public water

Public water systems in Houston 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 Houston 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 Houston County Prevalence MN Average Source Year
PFOA Cancer prevalence 8.6% 7.0% 2020
Arsenic Kidney disease rate 3.2% 2.9% 2020
Lead Heart disease rate 5.4% 6.6% 2020

Source: CDC PLACES county-level estimates. Raw data: Download Houston 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: 2026-07-15

Full methodology →