Full contaminant data, sample history, and sourcing for Salem County. For readers who want to go beyond the summary.
Contaminant Data — All Analytes
953 well testing events on record, covering
22 analytes.
Data spans 1950 to 2023.
Contaminant
Samples
Years
Detection Rate
Distribution LowModHigh
vs. Limit
vs. NJ Avg
Iron
356
1950–2023
88%
208% of limit
↓ 56% below
PFOA
municipal
27
2020–2025
44%
288% of limit
↑ 45% above
Manganese
351
1950–2023
96%
78% of limit
↓ 84% below
Nitrate
319
1950–2023
88%
25% of limit
~ typical
Radon
56
1988–2023
100%
17% of limit
↓ 60% below
Chloride
874
1950–2023
100%
17% of limit
↓ 40% below
PFNA
municipal
27
2020–2025
11%
62% of limit
↑ 43% above
PFOS
municipal
28
2020–2025
11%
92% of limit
↓ 45% below
Sulfate
364
1950–2023
97%
6% of limit
↓ 62% below
Arsenic
174
1975–2023
48%
2% of limit
↓ 85% below
Fluoride
296
1950–2023
76%
5% of limit
~ typical
HFPO-DA (GenX)
municipal
28
2020–2025
0%
—
—
Lead
163
1975–2023
35%
2% of limit
↓ 94% below
Nitrite
216
1973–2023
16%
1% of limit
↓ 23% below
PFHxS
municipal
26
2020–2025
0%
—
—
Uranium
39
1988–2022
64%
0% of limit
↓ 95% below
E. coli
2
2003–2022
17%
—
~ typical
Hardness
370
1950–2023
100%
—
↓ 49% below
PFBS
municipal
20
2020–2025
0%
—
—
pH
678
1950–2023
100%
—
~ typical
Sodium
442
1950–2023
100%
—
↓ 43% below
Total Coliform
2
2003–2022
17%
—
~ 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 NJ.
Compare your result with Salem County
Of the 174 arsenic tests on record for Salem County (1975–2023),
52% found none.
Of the 874 chloride tests on record for Salem County (1950–2023),
0% found none, and half were below 43 mg/L.
Of the 296 fluoride tests on record for Salem County (1950–2023),
24% found none, and half were below 100 µg/L.
Of the 356 iron tests on record for Salem County (1950–2023),
12% found none, and half were below 380 µg/L.
Of the 163 lead tests on record for Salem County (1975–2023),
65% found none.
Of the 351 manganese tests on record for Salem County (1950–2023),
4% found none, and half were below 34.5 µg/L.
Of the 319 nitrate tests on record for Salem County (1950–2023),
12% found none, and half were below 1.4 mg/L.
Of the 364 sulfate tests on record for Salem County (1950–2023),
3% found none, and half were below 13.8 mg/L.
Of the 39 uranium tests on record for Salem County (1988–2022),
36% found none, and half were below 40 ng/L.
Data Coverage & Gaps
Well-sampled analytes (15+ samples)
Iron 356 samples
PFOA 27 samples
Manganese 351 samples
Nitrate 319 samples
Radon 56 samples
Chloride 874 samples
PFNA 27 samples
PFOS 28 samples
Sulfate 364 samples
Arsenic 174 samples
Fluoride 296 samples
HFPO-DA (GenX) 28 samples
Lead 163 samples
Nitrite 216 samples
PFHxS 26 samples
Uranium 39 samples
Hardness 370 samples
PFBS 20 samples
pH 678 samples
Sodium 442 samples
Limited data (<15 samples) — interpret with caution
E. coli 2 samples
Total Coliform 2 samples
Public vs. Private Water in Salem County
106Active public water systems
68,320Residents on public water
34%Households on private wells
Public water systems in Salem 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 Salem 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 Salem 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 Salem County. Census data explorer →
USGS Aquifer Atlas — principal aquifer type underlying Salem 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 Salem County, used in contamination risk scoring. TRI Explorer →
EPA Superfund NPL — National Priorities List sites in or near Salem 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 NJ with at least one sample for that analyte.