Full contaminant data, sample history, and sourcing for Shelby County. For readers who want to go beyond the summary.
Contaminant Data — All Analytes
118 well testing events on record, covering
20 analytes.
Data spans 1965 to 2022.
Contaminant
Samples
Years
Detection Rate
Distribution LowModHigh
vs. Limit
vs. OH Avg
Iron
109
1986–2020
95%
708% of limit
↑ 62% above
Arsenic
108
1986–2020
98%
55% of limit
↑ 249% above
Manganese
106
1986–2020
98%
56% of limit
↓ 68% below
Sulfate
43
2000–2020
95%
28% of limit
↓ 36% below
Nitrate
38
1986–2020
16%
4% of limit
~ typical
Chloride
108
1986–2020
94%
2% of limit
↓ 85% below
Fluoride
83
1996–2020
100%
30% of limit
↑ 192% above
HFPO-DA (GenX)
municipal
6
2023–2024
0%
—
—
Lead
107
1986–2020
62%
0% of limit
↓ 100% below
Nitrite
38
1991–2020
18%
0% of limit
↓ 37% below
PFHxS
municipal
6
2023–2024
0%
—
—
PFNA
municipal
6
2023–2024
0%
—
—
PFOA
municipal
6
2023–2024
0%
—
—
PFOS
municipal
6
2023–2024
0%
—
—
Radon
2
2000
100%
8% of limit
↓ 62% below
Uranium
34
2000–2020
85%
2% of limit
~ typical
Hardness
107
1986–2020
100%
—
↑ 22% above
PFBS
municipal
6
2023–2024
0%
—
—
pH
95
1986–2020
100%
—
~ typical
Sodium
109
1986–2020
100%
—
↓ 40% 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 OH.
Compare your result with Shelby County
Of the 108 arsenic tests on record for Shelby County (1986–2020),
2% found none, and half were below 5.35 µg/L.
Of the 108 chloride tests on record for Shelby County (1986–2020),
6% found none, and half were below 5.6 mg/L.
Of the 83 fluoride tests on record for Shelby County (1996–2020),
0% found none, and half were below 1.2 mg/L.
Of the 109 iron tests on record for Shelby County (1986–2020),
5% found none, and half were below 2.1 mg/L.
Of the 107 lead tests on record for Shelby County (1986–2020),
38% found none.
Of the 106 manganese tests on record for Shelby County (1986–2020),
2% found none, and half were below 26.2 µg/L.
Of the 38 nitrate tests on record for Shelby County (1986–2020),
84% found none.
Of the 43 sulfate tests on record for Shelby County (2000–2020),
5% found none, and half were below 70.7 mg/L.
Of the 34 uranium tests on record for Shelby County (2000–2020),
15% found none, and half were below 0.506 µg/L.
Data Coverage & Gaps
Well-sampled analytes (15+ samples)
Iron 109 samples
Arsenic 108 samples
Manganese 106 samples
Sulfate 43 samples
Nitrate 38 samples
Chloride 108 samples
Fluoride 83 samples
Lead 107 samples
Nitrite 38 samples
Uranium 34 samples
Hardness 107 samples
pH 95 samples
Sodium 109 samples
Limited data (<15 samples) — interpret with caution
Radon 2 samples
No private-well PFAS data for Shelby County
We have no private well sampling data for PFAS compounds (PFOA, PFOS, PFNA, and related chemicals) in Shelby 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 →
Public vs. Private Water in Shelby County
41Active public water systems
36,172Residents on public water
39%Households on private wells
Public water systems in Shelby 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 Shelby 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 Shelby 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 Shelby County. Census data explorer →
USGS Aquifer Atlas — principal aquifer type underlying Shelby 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 Shelby County, used in contamination risk scoring. TRI Explorer →
EPA Superfund NPL — National Priorities List sites in or near Shelby 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 OH with at least one sample for that analyte.