Data & Methodology — Orange County

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

Contaminant Data — All Analytes

150 well testing events on record, covering 16 analytes. Data spans 1952 to 2025.

Contaminant Samples Years Detection Rate Distribution LowModHigh vs. Limit vs. VT Avg
Radon 52 2002 100%
617% of limit ↑ 38% above
Manganese 713 1966–2017 100%
6% of limit ↓ 99% below
Iron 563 1966–2017 100%
17% of limit ↓ 92% below
Lead 2071 2002–2017 92%
13% of limit ↓ 81% below
Arsenic 1220 2002–2017 32%
40% of limit ↓ 22% below
Chloride 1047 1966–2017 100%
1% of limit ↓ 88% below
Nitrate 1113 1966–2017 100%
2% of limit ↓ 24% below
Fluoride 1293 1966–2017 99%
1% of limit ↓ 60% below
Uranium 1111 2002–2017 88%
3% of limit ↓ 59% below
Nitrite 1095 1981–2017 95%
2% of limit ~ typical
Sulfate 10 1966–2017 100%
6% of limit ~ typical
Total Coliform 1 2002–2017 0%
— —
Sodium 550 1966–2017 100%
— ↓ 60% below
pH 192 1966–2017 100%
— ~ typical
Hardness 377 1966–2017 100%
— ↓ 35% below
E. coli 1 2002–2017 100%
— ↓ 77% 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 VT.

Compare your result with Orange County

Of the 1220 arsenic tests on record for Orange County (2002–2017), 68% found none.

Of the 1047 chloride tests on record for Orange County (1966–2017), 0% found none, and half were below 2.5 mg/L.

Of the 1293 fluoride tests on record for Orange County (1966–2017), 1% found none, and half were below 50 µg/L.

Of the 563 iron tests on record for Orange County (1966–2017), 0% found none, and half were below 50 µg/L.

Of the 2071 lead tests on record for Orange County (2002–2017), 8% found none, and half were below 2 µg/L.

Of the 713 manganese tests on record for Orange County (1966–2017), 0% found none, and half were below 3 µg/L.

Of the 1113 nitrate tests on record for Orange County (1966–2017), 0% found none, and half were below 250 µg/L.

Of the 1111 uranium tests on record for Orange County (2002–2017), 12% found none, and half were below 1 µg/L.

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Data Coverage & Gaps

Well-sampled analytes (15+ samples)

  • Radon 52 samples
  • Manganese 713 samples
  • Iron 563 samples
  • Lead 2071 samples
  • Arsenic 1220 samples
  • Chloride 1047 samples
  • Nitrate 1113 samples
  • Fluoride 1293 samples
  • Uranium 1111 samples
  • Nitrite 1095 samples
  • Sodium 550 samples
  • pH 192 samples
  • Hardness 377 samples

Limited data (<15 samples) — interpret with caution

  • Sulfate 10 samples
  • Total Coliform 1 sample
  • E. coli 1 sample

No private-well PFAS data for Orange County

We have no private well sampling data for PFAS compounds (PFOA, PFOS, PFNA, and related chemicals) in Orange County. PFAS testing for private wells requires a dedicated lab panel (~$300–$500). If you are near a military base, airport, or industrial site, consider testing proactively. Learn more about PFAS →

Public vs. Private Water in Orange County

70 Active public water systems
20,846 Residents on public water
66% Households on private wells

Public water systems in Orange 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 Orange 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 Orange County Prevalence VT Average Source Year
Arsenic Cancer prevalence 8.1% 7.0% 2020
Arsenic Kidney disease rate 3.1% 2.8% 2020
Lead Heart disease rate 7.5% 6.3% 2020

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

Last updated: 2026-07-31

Full methodology →