Full contaminant data, sample history, and sourcing for Orleans County. For readers who want to go beyond the summary.
Contaminant Data — All Analytes
6 well testing events on record, covering
20 analytes.
Data spans 1956 to 2025.
Contaminant
Samples
Years
Detection Rate
Distribution LowModHigh
vs. Limit
vs. VT Avg
Radon
214
—
100%
430% of limit
~ typical
Manganese
473
1966
100%
6% of limit
↓ 99% below
Iron
338
1966
100%
17% of limit
↓ 92% below
Uranium
768
—
90%
7% of limit
~ typical
Arsenic
1050
—
63%
20% of limit
↓ 61% below
Lead
1709
—
73%
13% of limit
↓ 81% below
Chloride
911
1966
100%
1% of limit
↓ 88% below
Nitrate
1307
1966
100%
2% of limit
↓ 24% below
Fluoride
1152
1966
100%
3% of limit
~ typical
HFPO-DA (GenX)
municipal
6
2023–2024
0%
—
—
Nitrite
1254
—
100%
2% of limit
~ typical
PFHxS
municipal
6
2023–2024
0%
—
—
PFNA
municipal
6
2023–2024
0%
—
—
PFOA
municipal
6
2023–2024
0%
—
—
PFOS
municipal
6
2023–2024
0%
—
—
Sulfate
1
1966
100%
7% of limit
~ typical
Hardness
206
1966
100%
—
↓ 38% below
PFBS
municipal
6
2023–2024
0%
—
—
pH
74
1966
100%
—
~ typical
Sodium
322
1966
100%
—
↓ 60% 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 Orleans County
Of the 1050 arsenic tests on record for Orleans County,
37% found none, and half were below 1 µg/L.
Of the 911 chloride tests on record for Orleans County (1966),
0% found none, and half were below 2.5 mg/L.
Of the 1152 fluoride tests on record for Orleans County (1966),
0% found none, and half were below 120 µg/L.
Of the 338 iron tests on record for Orleans County (1966),
0% found none, and half were below 50 µg/L.
Of the 1709 lead tests on record for Orleans County,
27% found none, and half were below 1 µg/L.
Of the 473 manganese tests on record for Orleans County (1966),
0% found none, and half were below 3 µg/L.
Of the 1307 nitrate tests on record for Orleans County (1966),
0% found none, and half were below 250 µg/L.
Of the 768 uranium tests on record for Orleans County,
10% found none, and half were below 1 µg/L.
Data Coverage & Gaps
Well-sampled analytes (15+ samples)
Radon 214 samples
Manganese 473 samples
Iron 338 samples
Uranium 768 samples
Arsenic 1050 samples
Lead 1709 samples
Chloride 911 samples
Nitrate 1307 samples
Fluoride 1152 samples
Nitrite 1254 samples
Hardness 206 samples
pH 74 samples
Sodium 322 samples
Limited data (<15 samples) — interpret with caution
Sulfate 1 sample
No private-well PFAS data for Orleans County
We have no private well sampling data for PFAS compounds (PFOA, PFOS, PFNA, and related chemicals) in Orleans 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 Orleans County
73Active public water systems
26,600Residents on public water
48%Households on private wells
Public water systems in Orleans 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 Orleans 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.
This report aggregates data from the following public databases:
Water Quality Portal (WQP) — groundwater sample results for Orleans County from EPA, USGS, and state agencies. Browse WQP data →
EPA Safe Drinking Water Information System (SDWIS) — public water system inventory used to estimate the share of residents on private wells. Browse SDWIS →
Census ACS 5-Year Estimates — well and cistern household counts (variable DP04_0074E) used to calculate the private-well percentage for Orleans County. Census data explorer →
USGS Aquifer Atlas — principal aquifer type underlying Orleans County, which informs which contaminants are geologically likely. USGS Aquifer Atlas →
EPA UCMR 5 (2023–2025) — PFAS occurrence data from public water systems, used as a proxy indicator for aquifer PFAS exposure. Rows marked "municipal" in the table above come from this source. About UCMR 5 →
EPA Toxics Release Inventory (TRI) — industrial facility chemical releases near Orleans County, used in contamination risk scoring. TRI Explorer →
EPA Superfund NPL — National Priorities List sites in or near Orleans County, used in contamination risk scoring. Superfund site search →
CDC PLACES — county-level health outcome prevalence (kidney disease, cancer, heart disease) correlated with detected contaminants. About CDC PLACES →
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.