Full contaminant data, sample history, and sourcing for Snyder County. For readers who want to go beyond the summary.
Contaminant Data — All Analytes
80 well testing events on record, covering
22 analytes.
Data spans 1934 to 2024.
Contaminant
Samples
Years
Detection Rate
Distribution LowModHigh
vs. Limit
vs. PA Avg
Manganese
35
1968–2022
97%
60% of limit
↓ 88% below
Radon
9
1993–2018
100%
88% of limit
↓ 32% below
Iron
39
1934–2022
97%
40% of limit
↓ 93% below
Arsenic
33
1974–2022
88%
10% of limit
↓ 66% below
PFOS
municipal
43
2024–2025
2%
184% of limit
↑ 44% above
Nitrate
47
1934–2022
94%
4% of limit
↓ 75% below
Chloride
40
1934–2022
100%
1% of limit
↓ 89% below
Fluoride
34
1954–2022
74%
2% of limit
↓ 44% below
HFPO-DA (GenX)
municipal
39
2024–2025
0%
—
—
Lead
28
1974–2022
7%
2% of limit
↓ 52% below
Nitrite
39
1981–2022
18%
2% of limit
↑ 33% above
PFHxS
municipal
7
2024–2025
0%
—
—
PFNA
municipal
7
2024–2025
0%
—
—
PFOA
municipal
43
2024–2025
0%
—
—
Sulfate
38
1934–2022
95%
4% of limit
↓ 77% below
Uranium
6
1993–2022
50%
0% of limit
↓ 88% below
E. coli
1
2005–2022
40%
—
~ typical
Hardness
40
1934–2022
100%
—
↓ 43% below
PFBS
municipal
39
2024–2025
13%
—
↓ 47% below
pH
44
1954–2022
100%
—
~ typical
Sodium
36
1934–2022
100%
—
↓ 66% below
Total Coliform
1
1993–2022
89%
—
~ 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 PA.
Compare your result with Snyder County
Of the 33 arsenic tests on record for Snyder County (1974–2022),
12% found none, and half were below 1 µg/L.
Of the 40 chloride tests on record for Snyder County (1934–2022),
0% found none, and half were below 3 mg/L.
Of the 34 fluoride tests on record for Snyder County (1954–2022),
26% found none, and half were below 100 µg/L.
Of the 39 iron tests on record for Snyder County (1934–2022),
3% found none, and half were below 110 µg/L.
Of the 28 lead tests on record for Snyder County (1974–2022),
93% found none.
Of the 35 manganese tests on record for Snyder County (1968–2022),
3% found none, and half were below 20 µg/L.
Of the 47 nitrate tests on record for Snyder County (1934–2022),
6% found none, and half were below 280 µg/L.
Of the 36 pfoa tests on record for Snyder County (2025),
100% found none.
Of the 36 pfos tests on record for Snyder County (2025),
97% found none.
Of the 38 sulfate tests on record for Snyder County (1934–2022),
5% found none, and half were below 10 mg/L.
Data Coverage & Gaps
Well-sampled analytes (15+ samples)
Manganese 35 samples
Iron 39 samples
Arsenic 33 samples
PFOS 43 samples
Nitrate 47 samples
Chloride 40 samples
Fluoride 34 samples
HFPO-DA (GenX) 39 samples
Lead 28 samples
Nitrite 39 samples
PFOA 43 samples
Sulfate 38 samples
Hardness 40 samples
PFBS 39 samples
pH 44 samples
Sodium 36 samples
Limited data (<15 samples) — interpret with caution
Radon 9 samples
Uranium 6 samples
E. coli 1 sample
Total Coliform 1 sample
Public vs. Private Water in Snyder County
49Active public water systems
23,485Residents on public water
60%Households on private wells
Public water systems in Snyder 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 Snyder 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 Snyder 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 Snyder County. Census data explorer →
USGS Aquifer Atlas — principal aquifer type underlying Snyder 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 Snyder County, used in contamination risk scoring. TRI Explorer →
EPA Superfund NPL — National Priorities List sites in or near Snyder 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 PA with at least one sample for that analyte.