Data & Methodology — Hunterdon County

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

Contaminant Data — All Analytes

333 well testing events on record, covering 20 analytes. Data spans 1923 to 2024.

Contaminant Samples Years Detection Rate Distribution LowModHigh vs. Limit vs. NJ Avg
PFOA municipal 80 2021–2025 52%
141% of limit ↓ 29% below
Radon 57 1986–2011 100%
37% of limit ~ typical
PFOS municipal 80 2021–2025 30%
131% of limit ↓ 23% below
Manganese 227 1968–2022 74%
21% of limit ↓ 96% below
Iron 227 1968–2022 69%
6% of limit ↓ 99% below
Arsenic 177 1983–2022 72%
30% of limit ↑ 80% above
Sulfate 228 1968–2022 100%
11% of limit ↓ 32% below
Lead 188 1983–2022 23%
4% of limit ↓ 84% below
Chloride 229 1968–2022 100%
6% of limit ↓ 80% below
Uranium 100 1985–2011 94%
7% of limit ↑ 61% above
Fluoride 173 1968–2022 76%
3% of limit ↓ 43% below
HFPO-DA (GenX) municipal 80 2021–2025 0%
— —
Nitrate 195 1968–2022 88%
17% of limit ↓ 30% below
Nitrite 186 1983–2022 20%
1% of limit ↓ 41% below
PFHxS municipal 80 2021–2025 6%
31% of limit ↓ 29% below
PFNA municipal 80 2021–2025 0%
— —
Sodium 225 1968–2022 100%
— ↓ 70% below
pH 290 1968–2022 100%
— ~ typical
PFBS municipal 79 2021–2025 15%
— ↓ 29% below
Hardness 212 1968–2022 99%
— ~ 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 NJ.

Compare your result with Hunterdon County

Of the 177 arsenic tests on record for Hunterdon County (1983–2022), 28% found none, and half were below 2 µg/L.

Of the 229 chloride tests on record for Hunterdon County (1968–2022), 0% found none, and half were below 14.4 mg/L.

Of the 173 fluoride tests on record for Hunterdon County (1968–2022), 24% found none, and half were below 100 µg/L.

Of the 227 iron tests on record for Hunterdon County (1968–2022), 31% found none, and half were below 8 µg/L.

Of the 188 lead tests on record for Hunterdon County (1983–2022), 77% found none.

Of the 227 manganese tests on record for Hunterdon County (1968–2022), 26% found none, and half were below 4.59 µg/L.

Of the 195 nitrate tests on record for Hunterdon County (1968–2022), 12% found none, and half were below 1.56 mg/L.

Of the 228 sulfate tests on record for Hunterdon County (1968–2022), 0% found none, and half were below 28.2 mg/L.

Of the 100 uranium tests on record for Hunterdon County (1985–2011), 6% found none, and half were below 2.2 µg/L.

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Data Coverage & Gaps

Well-sampled analytes (15+ samples)

  • PFOA 80 samples
  • Radon 57 samples
  • PFOS 80 samples
  • Manganese 227 samples
  • Iron 227 samples
  • Arsenic 177 samples
  • Sulfate 228 samples
  • Lead 188 samples
  • Chloride 229 samples
  • Uranium 100 samples
  • Fluoride 173 samples
  • HFPO-DA (GenX) 80 samples
  • Nitrate 195 samples
  • Nitrite 186 samples
  • PFHxS 80 samples
  • PFNA 80 samples
  • Sodium 225 samples
  • pH 290 samples
  • PFBS 79 samples
  • Hardness 212 samples

Public vs. Private Water in Hunterdon County

291 Active public water systems
88,316 Residents on public water
60% Households on private wells

Public water systems in Hunterdon 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 Hunterdon 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 Hunterdon County Prevalence NJ Average Source Year
Lead Heart disease rate 4.6% 5.8% 2020
Arsenic Cancer prevalence 7.7% 6.2% 2020
Arsenic Kidney disease rate 2.6% 2.7% 2020

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

Last updated: 2026-08-04

Full methodology →