Data & Methodology — Perry County

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

Contaminant Data — All Analytes

160 well testing events on record, covering 20 analytes. Data spans 1926 to 2021.

Contaminant Samples Years Detection Rate Distribution LowModHigh vs. Limit vs. PA Avg
Manganese 54 1966–1997 83%
140% of limit ↓ 72% below
Iron 61 1934–1997 95%
45% of limit ↓ 92% below
Radon 12 1993–2018 100%
14% of limit ↓ 89% below
PFOS municipal 152 2025 26%
147% of limit ~ typical
PFOA municipal 152 2025 22%
95% of limit ~ typical
Nitrate 91 1934–2018 93%
15% of limit ~ typical
PFHxS municipal 6 2025 0%
— —
PFNA municipal 6 2025 0%
— —
Fluoride 56 1966–1997 89%
2% of limit ↓ 44% below
HFPO-DA (GenX) municipal 134 2025 0%
— —
Nitrite 48 1980–2018 10%
1% of limit ↓ 33% below
Uranium 9 1993–1997 22%
3% of limit ↑ 45% above
Arsenic 25 1975–2018 16%
2% of limit ↓ 95% below
Chloride 83 1934–1997 95%
2% of limit ↓ 78% below
Lead 21 1980–1997 5%
1% of limit ↓ 86% below
Sulfate 58 1934–1997 83%
4% of limit ↓ 75% below
PFBS municipal 134 2025 19%
— ~ typical
pH 71 1966–2019 100%
— ~ typical
Sodium 56 1934–1997 70%
— ↓ 64% below
Hardness 61 1934–1997 95%
— ↓ 53% 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 PA.

Compare your result with Perry County

Of the 25 arsenic tests on record for Perry County (1975–2018), 84% found none.

Of the 83 chloride tests on record for Perry County (1934–1997), 5% found none, and half were below 5.9 mg/L.

Of the 56 fluoride tests on record for Perry County (1966–1997), 11% found none, and half were below 100 µg/L.

Of the 61 iron tests on record for Perry County (1934–1997), 5% found none, and half were below 130 µg/L.

Of the 21 lead tests on record for Perry County (1980–1997), 95% found none.

Of the 54 manganese tests on record for Perry County (1966–1997), 17% found none, and half were below 34 µg/L.

Of the 91 nitrate tests on record for Perry County (1934–2018), 7% found none, and half were below 1.11 mg/L.

Of the 146 pfoa tests on record for Perry County (2025), 77% found none.

Of the 146 pfos tests on record for Perry County (2025), 73% found none.

Of the 58 sulfate tests on record for Perry County (1934–1997), 17% found none, and half were below 10 mg/L.

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Data Coverage & Gaps

Well-sampled analytes (15+ samples)

  • Manganese 54 samples
  • Iron 61 samples
  • PFOS 152 samples
  • PFOA 152 samples
  • Nitrate 91 samples
  • Fluoride 56 samples
  • HFPO-DA (GenX) 134 samples
  • Nitrite 48 samples
  • Arsenic 25 samples
  • Chloride 83 samples
  • Lead 21 samples
  • Sulfate 58 samples
  • PFBS 134 samples
  • pH 71 samples
  • Sodium 56 samples
  • Hardness 61 samples

Limited data (<15 samples) — interpret with caution

  • Radon 12 samples
  • Uranium 9 samples

Public vs. Private Water in Perry County

98 Active public water systems
26,496 Residents on public water
72% Households on private wells

Public water systems in Perry 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 Perry 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 Perry County Prevalence PA Average Source Year
Nitrate Cancer prevalence 6.1% 7.0% 2020
Lead Heart disease rate 7.9% 7.2% 2020

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