Full contaminant data, sample history, and sourcing for Montgomery County. For readers who want to go beyond the summary.
Contaminant Data — All Analytes
207 well testing events on record, covering
23 analytes.
Data spans 1956 to 2023.
Contaminant
Samples
Years
Detection Rate
Distribution LowModHigh
vs. Limit
vs. NY Avg
Manganese
106
1970–2021
88%
55% of limit
↓ 82% below
Iron
114
1965–2021
76%
7% of limit
↓ 96% below
Nitrate
106
1967–2021
65%
37% of limit
↑ 214% above
Radon
31
1993–2021
100%
8% of limit
↓ 93% below
Sulfate
109
1965–2021
99%
15% of limit
~ typical
Chloride
115
1965–2021
100%
9% of limit
↓ 69% below
Lead
24
1970–2021
33%
1% of limit
↓ 83% below
Arsenic
24
1970–2021
71%
2% of limit
↓ 89% below
Fluoride
107
1967–2021
68%
5% of limit
~ typical
HFPO-DA (GenX)
municipal
8
2023–2024
0%
—
—
Nitrite
98
1970–2021
18%
1% of limit
↑ 83% above
PFHxS
municipal
8
2023–2024
0%
—
—
PFNA
municipal
8
2023–2024
0%
—
—
PFOA
municipal
8
2023–2024
0%
—
—
PFOS
municipal
8
2023–2024
0%
—
—
Uranium
15
1993–2021
93%
5% of limit
↑ 152% above
Total Coliform
7
2006–2021
0%
—
—
Sodium
107
1967–2021
100%
—
↓ 79% below
pH
198
1965–2021
100%
—
~ typical
PFBS
municipal
8
2023–2024
0%
—
—
Hardness
115
1965–2021
99%
—
↑ 61% above
Fecal Coliform
7
2006–2021
9%
—
~ typical
E. coli
7
2006–2021
9%
—
~ 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 NY.
Compare your result with Montgomery County
Of the 24 arsenic tests on record for Montgomery County (1970–2021),
29% found none, and half were below 0.2 µg/L.
Of the 115 chloride tests on record for Montgomery County (1965–2021),
0% found none, and half were below 23 mg/L.
Of the 107 fluoride tests on record for Montgomery County (1967–2021),
32% found none, and half were below 100 µg/L.
Of the 114 iron tests on record for Montgomery County (1965–2021),
24% found none, and half were below 9 µg/L.
Of the 24 lead tests on record for Montgomery County (1970–2021),
67% found none.
Of the 106 manganese tests on record for Montgomery County (1970–2021),
12% found none, and half were below 21.8 µg/L.
Of the 106 nitrate tests on record for Montgomery County (1967–2021),
35% found none, and half were below 788 µg/L.
Of the 109 sulfate tests on record for Montgomery County (1965–2021),
1% found none, and half were below 37 mg/L.
Data Coverage & Gaps
Well-sampled analytes (15+ samples)
Manganese 106 samples
Iron 114 samples
Nitrate 106 samples
Radon 31 samples
Sulfate 109 samples
Chloride 115 samples
Lead 24 samples
Arsenic 24 samples
Fluoride 107 samples
Nitrite 98 samples
Uranium 15 samples
Sodium 107 samples
pH 198 samples
Hardness 115 samples
Limited data (<15 samples) — interpret with caution
Total Coliform 7 samples
Fecal Coliform 7 samples
E. coli 7 samples
No private-well PFAS data for Montgomery County
We have no private well sampling data for PFAS compounds (PFOA, PFOS, PFNA, and related chemicals) in Montgomery 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 →
CDC Health Outcome Correlations
Where contaminants detected in Montgomery 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 Montgomery 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 Montgomery County. Census data explorer →
USGS Aquifer Atlas — principal aquifer type underlying Montgomery 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 Montgomery County, used in contamination risk scoring. TRI Explorer →
EPA Superfund NPL — National Priorities List sites in or near Montgomery 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 NY with at least one sample for that analyte.