Data & Methodology — Sullivan County

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

Contaminant Data — All Analytes

73 well testing events on record, covering 16 analytes. Data spans 1935 to 2023.

Contaminant Samples Years Detection Rate Distribution LowModHigh vs. Limit vs. PA Avg
Radon 28 2012–2017 100%
320% of limit ↑ 147% above
Manganese 43 1968–2023 91%
57% of limit ↓ 89% below
Iron 47 1935–2023 62%
33% of limit ↓ 94% below
Arsenic 57 2006–2023 63%
12% of limit ↓ 61% below
Chloride 47 1935–2023 98%
1% of limit ↓ 89% below
Fluoride 36 1968–2023 69%
2% of limit ↓ 66% below
Lead 35 2012–2023 71%
1% of limit ↓ 69% below
Nitrate 40 1935–2023 80%
3% of limit ↓ 85% below
Nitrite 35 2012–2023 17%
0% of limit ↓ 93% below
PFOA 8 2025 0%
— —
PFOS 8 2025 0%
— —
Sulfate 47 1935–2023 98%
1% of limit ↓ 92% below
Uranium 37 2012–2021 73%
1% of limit ↓ 67% below
Hardness 47 1935–2023 100%
— ↓ 58% below
pH 45 1968–2023 100%
— ~ typical
Sodium 44 1935–2023 100%
— ↓ 86% 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 Sullivan County

Of the 57 arsenic tests on record for Sullivan County (2006–2023), 37% found none, and half were below 0.19 µg/L.

Of the 47 chloride tests on record for Sullivan County (1935–2023), 2% found none, and half were below 1.75 mg/L.

Of the 36 fluoride tests on record for Sullivan County (1968–2023), 31% found none, and half were below 50 µg/L.

Of the 47 iron tests on record for Sullivan County (1935–2023), 38% found none, and half were below 6.7 µg/L.

Of the 35 lead tests on record for Sullivan County (2012–2023), 29% found none, and half were below 0.15 µg/L.

Of the 43 manganese tests on record for Sullivan County (1968–2023), 9% found none, and half were below 8.34 µg/L.

Of the 40 nitrate tests on record for Sullivan County (1935–2023), 20% found none, and half were below 260 µg/L.

Of the 47 sulfate tests on record for Sullivan County (1935–2023), 2% found none, and half were below 3.3 mg/L.

Of the 37 uranium tests on record for Sullivan County (2012–2021), 27% found none, and half were below 86 ng/L.

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Data Coverage & Gaps

Well-sampled analytes (15+ samples)

  • Radon 28 samples
  • Manganese 43 samples
  • Iron 47 samples
  • Arsenic 57 samples
  • Chloride 47 samples
  • Fluoride 36 samples
  • Lead 35 samples
  • Nitrate 40 samples
  • Nitrite 35 samples
  • Sulfate 47 samples
  • Uranium 37 samples
  • Hardness 47 samples
  • pH 45 samples
  • Sodium 44 samples

Limited data (<15 samples) — interpret with caution

  • PFOA 8 samples
  • PFOS 8 samples

Public vs. Private Water in Sullivan County

30 Active public water systems
3,178 Residents on public water
79% Households on private wells

Public water systems in Sullivan 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 Sullivan 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 Sullivan County Prevalence PA Average Source Year
Lead Heart disease rate 10.0% 7.2% 2020
Arsenic Cancer prevalence 6.1% 7.0% 2020
Arsenic Kidney disease rate 2.6% 3.0% 2020

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