Full contaminant data, sample history, and sourcing for Niagara County. For readers who want to go beyond the summary.
Contaminant Data — All Analytes
253 well testing events on record, covering
20 analytes.
Data spans 1948 to 2023.
Contaminant
Samples
Years
Detection Rate
Distribution LowModHigh
vs. Limit
vs. NY Avg
Sulfate
119
1948–2011
100%
208% of limit
↑ 1427% above
Lead
25
1982–2011
72%
1667% of limit
↑ 39661% above
Iron
60
1948–2011
97%
237% of limit
↑ 22% above
Manganese
35
1956–2011
100%
140% of limit
↓ 55% below
Chloride
159
1948–2011
100%
31% of limit
~ typical
Arsenic
24
1982–2011
100%
20% of limit
~ typical
Nitrate
44
1948–2011
73%
2% of limit
↓ 87% below
Fluoride
68
1948–2011
100%
23% of limit
↑ 315% above
HFPO-DA (GenX)
municipal
64
2023–2025
0%
—
—
Nitrite
14
1994–2011
7%
0% of limit
↓ 76% below
PFHxS
municipal
64
2023–2025
0%
—
—
PFNA
municipal
64
2023–2025
0%
—
—
PFOA
municipal
64
2023–2025
0%
—
—
PFOS
municipal
64
2023–2025
0%
—
—
Radon
4
2006–2011
100%
16% of limit
↓ 85% below
Uranium
4
2006–2011
100%
2% of limit
~ typical
Hardness
119
1948–2011
100%
—
↑ 386% above
PFBS
municipal
64
2023–2025
0%
—
—
pH
139
1948–2011
100%
—
~ typical
Sodium
52
1948–2011
100%
—
↑ 60% above
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 Niagara County
Of the 24 arsenic tests on record for Niagara County (1982–2011),
0% found none, and half were below 2 µg/L.
Of the 159 chloride tests on record for Niagara County (1948–2011),
0% found none, and half were below 77.7 mg/L.
Of the 68 fluoride tests on record for Niagara County (1948–2011),
0% found none, and half were below 930 µg/L.
Of the 60 iron tests on record for Niagara County (1948–2011),
3% found none, and half were below 675 µg/L.
Of the 25 lead tests on record for Niagara County (1982–2011),
28% found none, and half were below 200 µg/L.
Of the 35 manganese tests on record for Niagara County (1956–2011),
0% found none, and half were below 70 µg/L.
Of the 44 nitrate tests on record for Niagara County (1948–2011),
27% found none, and half were below 113 µg/L.
Of the 119 sulfate tests on record for Niagara County (1948–2011),
0% found none, and half were below 520 mg/L.
Data Coverage & Gaps
Well-sampled analytes (15+ samples)
Sulfate 119 samples
Lead 25 samples
Iron 60 samples
Manganese 35 samples
Chloride 159 samples
Arsenic 24 samples
Nitrate 44 samples
Fluoride 68 samples
Hardness 119 samples
pH 139 samples
Sodium 52 samples
Limited data (<15 samples) — interpret with caution
Nitrite 14 samples
Radon 4 samples
Uranium 4 samples
No private-well PFAS data for Niagara County
We have no private well sampling data for PFAS compounds (PFOA, PFOS, PFNA, and related chemicals) in Niagara 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 Niagara 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 Niagara 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 Niagara County. Census data explorer →
USGS Aquifer Atlas — principal aquifer type underlying Niagara 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 Niagara County, used in contamination risk scoring. TRI Explorer →
EPA Superfund NPL — National Priorities List sites in or near Niagara 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.