Full contaminant data, sample history, and sourcing for Crawford County. For readers who want to go beyond the summary.
Contaminant Data — All Analytes
156 well testing events on record, covering
20 analytes.
Data spans 1928 to 2023.
Contaminant
Samples
Years
Detection Rate
Distribution LowModHigh
vs. Limit
vs. PA Avg
Manganese
37
1967–2023
97%
150% of limit
↓ 70% below
Iron
41
1928–2023
100%
63% of limit
↓ 89% below
Radon
8
1996–2019
100%
9% of limit
↓ 93% below
Chloride
42
1928–2023
100%
3% of limit
↓ 72% below
PFOS
municipal
231
2023–2025
9%
116% of limit
~ typical
PFOA
municipal
230
2023–2025
3%
92% of limit
~ typical
Arsenic
8
2019–2023
62%
9% of limit
↓ 70% below
Fluoride
38
1967–2023
89%
6% of limit
↑ 40% above
HFPO-DA (GenX)
municipal
137
2023–2025
0%
—
—
Lead
8
2019–2023
12%
2% of limit
↓ 63% below
Nitrate
39
1928–2023
72%
1% of limit
↓ 95% below
Nitrite
16
1992–2023
25%
1% of limit
~ typical
PFHxS
municipal
6
2023–2024
0%
—
—
PFNA
municipal
6
2023–2024
0%
—
—
Sulfate
42
1928–2023
100%
7% of limit
↓ 58% below
Uranium
3
2019–2021
0%
—
—
Sodium
37
1928–2023
100%
—
↓ 43% below
pH
35
1967–2023
100%
—
~ typical
PFBS
municipal
136
2023–2025
2%
—
~ typical
Hardness
42
1928–2023
100%
—
~ 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 Crawford County
Of the 42 chloride tests on record for Crawford County (1928–2023),
0% found none, and half were below 7.4 mg/L.
Of the 38 fluoride tests on record for Crawford County (1967–2023),
11% found none, and half were below 200 µg/L.
Of the 41 iron tests on record for Crawford County (1928–2023),
0% found none, and half were below 190 µg/L.
Of the 37 manganese tests on record for Crawford County (1967–2023),
3% found none, and half were below 70 µg/L.
Of the 39 nitrate tests on record for Crawford County (1928–2023),
28% found none, and half were below 60 µg/L.
Of the 224 pfoa tests on record for Crawford County (2025),
97% found none.
Of the 225 pfos tests on record for Crawford County (2025),
92% found none.
Of the 42 sulfate tests on record for Crawford County (1928–2023),
0% found none, and half were below 18 mg/L.
Data Coverage & Gaps
Well-sampled analytes (15+ samples)
Manganese 37 samples
Iron 41 samples
Chloride 42 samples
PFOS 231 samples
PFOA 230 samples
Fluoride 38 samples
HFPO-DA (GenX) 137 samples
Nitrate 39 samples
Nitrite 16 samples
Sulfate 42 samples
Sodium 37 samples
pH 35 samples
PFBS 136 samples
Hardness 42 samples
Limited data (<15 samples) — interpret with caution
Radon 8 samples
Arsenic 8 samples
Lead 8 samples
Uranium 3 samples
Public vs. Private Water in Crawford County
180Active public water systems
55,253Residents on public water
68%Households on private wells
Public water systems in Crawford 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 Crawford 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 Crawford 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 Crawford County. Census data explorer →
USGS Aquifer Atlas — principal aquifer type underlying Crawford 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 Crawford County, used in contamination risk scoring. TRI Explorer →
EPA Superfund NPL — National Priorities List sites in or near Crawford 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.