Data & Methodology — Windsor County

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

Contaminant Data — All Analytes

31 well testing events on record, covering 22 analytes. Data spans 1952 to 2025.

Contaminant Samples Years Detection Rate Distribution LowModHigh vs. Limit vs. VT Avg
Radon 164 1995–2002 100%
268% of limit ↓ 40% below
Manganese 982 1966–2017 100%
6% of limit ↓ 99% below
Iron 796 1966–2017 100%
17% of limit ↓ 92% below
Lead 3979 2002–2017 98%
7% of limit ↓ 91% below
Chloride 1691 1966–2017 100%
1% of limit ↓ 88% below
Arsenic 1965 1995–2017 26%
10% of limit ↓ 81% below
Uranium 1748 1995–2017 77%
3% of limit ↓ 59% below
Nitrate 1262 1966–2017 100%
2% of limit ↓ 24% below
Fluoride 1953 1966–2017 100%
1% of limit ↓ 60% below
HFPO-DA (GenX) municipal 9 2023–2025 0%
— —
Nitrite 1236 1994–2017 99%
2% of limit ~ typical
PFHxS municipal 9 2023–2025 0%
— —
PFNA municipal 9 2023–2025 0%
— —
PFOA municipal 9 2023–2025 0%
— —
PFOS municipal 9 2023–2025 0%
— —
Sulfate 45 1966–2017 100%
5% of limit ~ typical
Sodium 768 1966–2017 100%
— ↓ 60% below
E. coli 1 2002–2017 97%
— ↓ 93% below
Hardness 493 1966–2017 100%
— ↓ 45% below
Total Coliform 1 2002–2017 0%
— —
pH 64 1966–2017 100%
— ~ typical
PFBS municipal 9 2023–2025 11%
— ~ 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 VT.

Compare your result with Windsor County

Of the 1965 arsenic tests on record for Windsor County (1995–2017), 74% found none.

Of the 1691 chloride tests on record for Windsor County (1966–2017), 0% found none, and half were below 2.5 mg/L.

Of the 1953 fluoride tests on record for Windsor County (1966–2017), 0% found none, and half were below 50 µg/L.

Of the 796 iron tests on record for Windsor County (1966–2017), 1% found none, and half were below 50 µg/L.

Of the 3979 lead tests on record for Windsor County (2002–2017), 2% found none, and half were below 1 µg/L.

Of the 982 manganese tests on record for Windsor County (1966–2017), 0% found none, and half were below 3 µg/L.

Of the 1262 nitrate tests on record for Windsor County (1966–2017), 0% found none, and half were below 250 µg/L.

Of the 45 sulfate tests on record for Windsor County (1966–2017), 0% found none, and half were below 11.5 mg/L.

Of the 1748 uranium tests on record for Windsor County (1995–2017), 23% found none, and half were below 1 µg/L.

Have a number from your lab? Enter it to see where it falls. Nothing is sent anywhere.

Want the full picture for your well? Check all your results.

Data Coverage & Gaps

Well-sampled analytes (15+ samples)

  • Radon 164 samples
  • Manganese 982 samples
  • Iron 796 samples
  • Lead 3979 samples
  • Chloride 1691 samples
  • Arsenic 1965 samples
  • Uranium 1748 samples
  • Nitrate 1262 samples
  • Fluoride 1953 samples
  • Nitrite 1236 samples
  • Sulfate 45 samples
  • Sodium 768 samples
  • Hardness 493 samples
  • pH 64 samples

Limited data (<15 samples) — interpret with caution

  • E. coli 1 sample
  • Total Coliform 1 sample

No private-well PFAS data for Windsor County

We have no private well sampling data for PFAS compounds (PFOA, PFOS, PFNA, and related chemicals) in Windsor County. PFAS has been detected in local public water systems (UCMR 5 data) — indicated by the "municipal" badge in the table above — but this does not directly indicate private well contamination. 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 Windsor County

164 Active public water systems
68,857 Residents on public water
38% Households on private wells

Public water systems in Windsor 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 Windsor 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 Windsor County Prevalence VT Average Source Year
Arsenic Cancer prevalence 6.1% 7.0% 2020
Arsenic Kidney disease rate 2.4% 2.8% 2020
Lead Heart disease rate 7.5% 6.3% 2020

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