Data & Methodology — Passaic County

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

Contaminant Data — All Analytes

142 well testing events on record, covering 20 analytes. Data spans 1923 to 2025.

Contaminant Samples Years Detection Rate Distribution LowModHigh vs. Limit vs. NJ Avg
PFOA municipal 108 2022–2025 70%
158% of limit ↓ 21% below
Manganese 67 1969–2022 87%
66% of limit ↓ 86% below
PFOS municipal 108 2022–2025 32%
148% of limit ~ typical
Radon 12 1997–2014 100%
23% of limit ↓ 46% below
Iron 67 1969–2022 82%
13% of limit ↓ 97% below
Chloride 67 1969–2022 100%
16% of limit ↓ 47% below
Sulfate 67 1969–2022 100%
10% of limit ↓ 40% below
Lead 50 1987–2022 40%
4% of limit ↓ 84% below
Arsenic 51 1987–2022 55%
5% of limit ↓ 69% below
Fluoride 61 1969–2022 77%
2% of limit ↓ 52% below
HFPO-DA (GenX) municipal 108 2022–2025 0%
— —
Nitrate 70 1969–2022 89%
9% of limit ↓ 63% below
Nitrite 61 1987–2022 23%
1% of limit ↓ 47% below
PFHxS municipal 107 2022–2025 9%
31% of limit ↓ 29% below
PFNA municipal 108 2022–2025 1%
30% of limit ↓ 31% below
Uranium 14 1997–2014 71%
25% of limit ↑ 452% above
PFBS municipal 108 2022–2025 19%
— ↓ 29% below
pH 75 1969–2022 100%
— ~ typical
Sodium 63 1969–2022 100%
— ↓ 65% below
Hardness 62 1969–2022 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 NJ.

Compare your result with Passaic County

Of the 51 arsenic tests on record for Passaic County (1987–2022), 45% found none, and half were below 70 ng/L.

Of the 67 chloride tests on record for Passaic County (1969–2022), 0% found none, and half were below 39 mg/L.

Of the 61 fluoride tests on record for Passaic County (1969–2022), 23% found none, and half were below 60 µg/L.

Of the 67 iron tests on record for Passaic County (1969–2022), 18% found none, and half were below 20 µg/L.

Of the 50 lead tests on record for Passaic County (1987–2022), 60% found none.

Of the 67 manganese tests on record for Passaic County (1969–2022), 13% found none, and half were below 17.6 µg/L.

Of the 70 nitrate tests on record for Passaic County (1969–2022), 11% found none, and half were below 826 µg/L.

Of the 67 sulfate tests on record for Passaic County (1969–2022), 0% found none, and half were below 25 mg/L.

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Data Coverage & Gaps

Well-sampled analytes (15+ samples)

  • PFOA 108 samples
  • Manganese 67 samples
  • PFOS 108 samples
  • Iron 67 samples
  • Chloride 67 samples
  • Sulfate 67 samples
  • Lead 50 samples
  • Arsenic 51 samples
  • Fluoride 61 samples
  • HFPO-DA (GenX) 108 samples
  • Nitrate 70 samples
  • Nitrite 61 samples
  • PFHxS 107 samples
  • PFNA 108 samples
  • PFBS 108 samples
  • pH 75 samples
  • Sodium 63 samples
  • Hardness 62 samples

Limited data (<15 samples) — interpret with caution

  • Radon 12 samples
  • Uranium 14 samples

Public vs. Private Water in Passaic County

148 Active public water systems
478,895 Residents on public water
7% Households on private wells

Public water systems in Passaic 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 Passaic 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 Passaic County Prevalence NJ Average Source Year
Lead Heart disease rate 5.7% 5.8% 2020
PFOA Cancer prevalence 5.9% 6.2% 2020

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