Data & Methodology — Indiana County

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

Contaminant Data — All Analytes

15503 total samples analyzed across 22 analytes. Data spans 1959 to 2018.

Contaminant Samples Years Detection Rate Distribution LowModHigh vs. Limit vs. PA Avg
Lead 2 1986–1987 50%
667% of limit ↑ 855% above
Manganese 8 1959–1968 88%
1360% of limit ↑ 123% above
Iron 10 1959–1968 90%
167% of limit ↓ 37% below
Radon 17 1995–2014 100%
60% of limit ↓ 67% below
Sulfate 61 1959–1987 98%
35% of limit ~ typical
PFOS municipal 53 2025 13%
0% of limit ↓ 100% below
Uranium 8 1999–2003 100%
2% of limit ~ typical
PFOA municipal 53 2025 13%
0% of limit ↓ 100% below
HFPO-DA (GenX) municipal 42 2025 0%
0% of limit —
Chloride 33 1959–1987 97%
6% of limit ↓ 61% below
Nitrite 3 1983–2009 67%
4% of limit ↑ 23% above
PFNA municipal 15 2023–2025 0%
0% of limit —
PFHxS municipal 15 2023–2025 0%
0% of limit —
Fluoride 5 1959–1965 80%
6% of limit ↑ 52% above
Nitrate 1 1964 0%
— —
Arsenic 1 1979 0%
— —
Hardness 1 1986 0% — — —
E. coli 1 2018 0%
— —
Sodium 73 1959–1987 99% — — ↓ 82% below
Fecal Coliform 1 2006 0%
— —
pH 19 1959–1987 95% — — ↓ 28% below
PFBS municipal 42 2025 5%
— ↓ 100% 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.

Data Coverage & Gaps

Well-sampled analytes (15+ samples)

  • Radon 17 samples
  • Sulfate 61 samples
  • PFOS 53 samples
  • PFOA 53 samples
  • HFPO-DA (GenX) 42 samples
  • Chloride 33 samples
  • Sodium 73 samples
  • pH 19 samples
  • PFBS 42 samples

Limited data (<15 samples) — interpret with caution

  • Lead 2 samples
  • Manganese 8 samples
  • Iron 10 samples
  • Uranium 8 samples
  • Nitrite 3 samples
  • Fluoride 5 samples
  • Nitrate 1 sample
  • Arsenic 1 sample
  • Hardness 1 sample
  • E. coli 1 sample
  • Fecal Coliform 1 sample

Public vs. Private Water in Indiana County

53 Active public water systems
54,205 Residents on public water
35% Households on private wells

Public water systems in Indiana 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 Indiana 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 Indiana County Prevalence PA Average Source Year
Lead Heart disease rate 6.5% 7.2% 2020
PFOS Cancer prevalence 6.1% 7.0% 2020

Source: CDC PLACES county-level estimates. Raw data: Download Indiana 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: 2026-05-28

Full methodology →