Full contaminant data, sample history, and sourcing for Richmond County. For readers who want to go beyond the summary.
Contaminant Data — All Analytes
74 well testing events on record, covering
17 analytes.
Data spans 1974 to 2025.
Contaminant
Samples
Years
Detection Rate
Distribution LowModHigh
vs. Limit
vs. NY Avg
Manganese
67
2005–2012
100%
324% of limit
~ typical
Iron
67
2005–2012
100%
154% of limit
~ typical
Chloride
67
2005–2012
100%
39% of limit
↑ 33% above
Nitrate
67
2005–2012
82%
19% of limit
↑ 64% above
Arsenic
67
2005–2012
72%
12% of limit
↓ 33% below
Fluoride
67
2005–2012
78%
3% of limit
↓ 51% below
HFPO-DA (GenX)
municipal
16
2023–2025
0%
—
—
Lead
67
2005–2012
90%
3% of limit
↓ 32% below
Nitrite
67
2005–2012
31%
0% of limit
↓ 76% below
PFHxS
municipal
16
2023–2025
0%
—
—
PFNA
municipal
16
2023–2025
0%
—
—
PFOA
municipal
16
2023–2025
0%
—
—
PFOS
municipal
16
2023–2025
0%
—
—
Sulfate
67
2005–2012
100%
13% of limit
~ typical
PFBS
municipal
16
2023–2025
0%
—
—
pH
67
2005–2012
100%
—
~ typical
Sodium
67
2005–2012
100%
—
↓ 42% 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 NY.
Compare your result with Richmond County
Of the 67 arsenic tests on record for Richmond County (2005–2012),
28% found none, and half were below 1 µg/L.
Of the 67 chloride tests on record for Richmond County (2005–2012),
0% found none, and half were below 98.3 mg/L.
Of the 67 fluoride tests on record for Richmond County (2005–2012),
22% found none, and half were below 90 µg/L.
Of the 67 iron tests on record for Richmond County (2005–2012),
0% found none, and half were below 463 µg/L.
Of the 67 lead tests on record for Richmond County (2005–2012),
10% found none, and half were below 0.33 µg/L.
Of the 67 manganese tests on record for Richmond County (2005–2012),
0% found none, and half were below 162 µg/L.
Of the 67 nitrate tests on record for Richmond County (2005–2012),
18% found none, and half were below 1.23 mg/L.
Of the 67 sulfate tests on record for Richmond County (2005–2012),
0% found none, and half were below 31.4 mg/L.
Data Coverage & Gaps
Well-sampled analytes (15+ samples)
Manganese 67 samples
Iron 67 samples
Chloride 67 samples
Nitrate 67 samples
Arsenic 67 samples
Fluoride 67 samples
Lead 67 samples
Nitrite 67 samples
Sulfate 67 samples
pH 67 samples
Sodium 67 samples
No private-well PFAS data for Richmond County
We have no private well sampling data for PFAS compounds (PFOA, PFOS, PFNA, and related chemicals) in Richmond 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 Richmond 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 Richmond 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 Richmond County. Census data explorer →
USGS Aquifer Atlas — principal aquifer type underlying Richmond 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 Richmond County, used in contamination risk scoring. TRI Explorer →
EPA Superfund NPL — National Priorities List sites in or near Richmond 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.