Data & Methodology — Fayette County

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

Contaminant Data — All Analytes

134 well testing events on record, covering 20 analytes. Data spans 1925 to 2023.

Contaminant Samples Years Detection Rate Distribution LowModHigh vs. Limit vs. PA Avg
Manganese 43 1964–2011 98%
431% of limit ~ typical
Iron 67 1926–2011 93%
522% of limit ~ typical
Radon 5 1996–2011 100%
9% of limit ↓ 93% below
Sulfate 66 1926–2011 95%
6% of limit ↓ 68% below
Lead 18 1964–2011 11%
98% of limit ↑ 2013% above
Nitrate 47 1926–2011 66%
3% of limit ↓ 82% below
Arsenic 34 1986–2011 82%
2% of limit ↓ 94% below
Chloride 53 1926–2011 100%
4% of limit ↓ 63% below
Fluoride 23 1964–2011 39%
5% of limit ~ typical
HFPO-DA (GenX) municipal 99 2023–2025 0%
— —
Nitrite 32 1996–2011 12%
1% of limit ↓ 47% below
PFHxS municipal 77 2023–2025 0%
— —
PFNA municipal 77 2023–2025 0%
— —
PFOA municipal 109 2023–2025 3%
19% of limit ↓ 80% below
PFOS municipal 109 2023–2025 2%
10% of limit ↓ 92% below
Uranium 16 1996–2011 75%
0% of limit ↓ 78% below
Sodium 36 1926–2011 100%
— ↓ 55% below
pH 56 1964–2011 100%
— ~ typical
PFBS municipal 99 2023–2025 2%
— ↓ 88% below
Hardness 51 1926–2011 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 PA.

Compare your result with Fayette County

Of the 34 arsenic tests on record for Fayette County (1986–2011), 18% found none, and half were below 0.125 µg/L.

Of the 53 chloride tests on record for Fayette County (1926–2011), 0% found none, and half were below 9.8 mg/L.

Of the 23 fluoride tests on record for Fayette County (1964–2011), 61% found none.

Of the 67 iron tests on record for Fayette County (1926–2011), 7% found none, and half were below 1.1 mg/L.

Of the 43 manganese tests on record for Fayette County (1964–2011), 2% found none, and half were below 191 µg/L.

Of the 47 nitrate tests on record for Fayette County (1926–2011), 34% found none, and half were below 130 µg/L.

Of the 32 pfoa tests on record for Fayette County (2025), 91% found none.

Of the 32 pfos tests on record for Fayette County (2025), 94% found none.

Of the 66 sulfate tests on record for Fayette County (1926–2011), 5% found none, and half were below 13.1 mg/L.

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Data Coverage & Gaps

Well-sampled analytes (15+ samples)

  • Manganese 43 samples
  • Iron 67 samples
  • Sulfate 66 samples
  • Lead 18 samples
  • Nitrate 47 samples
  • Arsenic 34 samples
  • Chloride 53 samples
  • Fluoride 23 samples
  • HFPO-DA (GenX) 99 samples
  • Nitrite 32 samples
  • PFOA 109 samples
  • PFOS 109 samples
  • Uranium 16 samples
  • Sodium 36 samples
  • pH 56 samples
  • PFBS 99 samples
  • Hardness 51 samples

Limited data (<15 samples) — interpret with caution

  • Radon 5 samples

Public vs. Private Water in Fayette County

41 Active public water systems
255,694 Residents on public water
13% Households on private wells

Public water systems in Fayette 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 Fayette 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 Fayette County Prevalence PA Average Source Year
Arsenic Cancer incidence rate 465.7% 448.6% 2022
Nitrate Cancer prevalence 8.1% 7.0% 2020
Arsenic Kidney disease rate 3.6% 3.0% 2020
Lead Heart disease rate 9.1% 7.2% 2020

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

Last updated: 2026-08-04

Full methodology →