Full contaminant data, sample history, and sourcing for Hamilton County. For readers who want to go beyond the summary.
Contaminant Data — All Analytes
259 well testing events on record, covering
23 analytes.
Data spans 1956 to 2024.
Contaminant
Samples
Years
Detection Rate
Distribution LowModHigh
vs. Limit
vs. FL Avg
Iron
90
1978–2025
100%
155% of limit
↓ 23% below
Manganese
90
1978–2025
100%
64% of limit
↑ 142% above
Arsenic
89
1978–2025
100%
10% of limit
↓ 23% below
Sulfate
156
1968–2025
100%
3% of limit
↓ 90% below
PFHxS
municipal
2
2023
0%
—
—
PFOS
municipal
2
2023
0%
—
—
Lead
91
1978–2025
97%
1% of limit
↓ 64% below
Nitrate
35
1968–2025
94%
0% of limit
↓ 85% below
Uranium
2
1978–2015
100%
3% of limit
↑ 244% above
Radon
2
1993–2015
100%
62% of limit
↑ 112% above
Chloride
156
1968–2025
100%
3% of limit
↓ 94% below
PFNA
municipal
2
2023
0%
—
—
PFOA
municipal
2
2023
0%
—
—
Fluoride
156
1968–2025
100%
5% of limit
↓ 32% below
HFPO-DA (GenX)
municipal
2
2023
0%
—
—
Nitrite
20
1978–2025
75%
3% of limit
↑ 143% above
PFBS
municipal
2
2023
0%
—
—
Fecal Coliform
32
2013–2021
100%
—
~ typical
E. coli
27
2015–2025
96%
—
~ typical
pH
248
1968–2025
100%
—
~ typical
Sodium
156
1968–2025
100%
—
↓ 93% below
Total Coliform
59
1980–2025
99%
—
~ typical
Hardness
26
1968–2015
100%
—
↓ 27% 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 FL.
Compare your result with Hamilton County
Of the 89 arsenic tests on record for Hamilton County (1978–2025),
0% found none, and half were below 1.01 µg/L.
Of the 156 chloride tests on record for Hamilton County (1968–2025),
0% found none, and half were below 7.7 mg/L.
Of the 156 fluoride tests on record for Hamilton County (1968–2025),
0% found none, and half were below 193 µg/L.
Of the 90 iron tests on record for Hamilton County (1978–2025),
0% found none, and half were below 464 µg/L.
Of the 91 lead tests on record for Hamilton County (1978–2025),
3% found none, and half were below 0.15 µg/L.
Of the 90 manganese tests on record for Hamilton County (1978–2025),
0% found none, and half were below 32 µg/L.
Of the 35 nitrate tests on record for Hamilton County (1968–2025),
6% found none, and half were below 30 µg/L.
Of the 156 sulfate tests on record for Hamilton County (1968–2025),
0% found none, and half were below 6.6 mg/L.
Data Coverage & Gaps
Well-sampled analytes (15+ samples)
Iron 90 samples
Manganese 90 samples
Arsenic 89 samples
Sulfate 156 samples
Lead 91 samples
Nitrate 35 samples
Chloride 156 samples
Fluoride 156 samples
Nitrite 20 samples
Fecal Coliform 32 samples
E. coli 27 samples
pH 248 samples
Sodium 156 samples
Total Coliform 59 samples
Hardness 26 samples
Limited data (<15 samples) — interpret with caution
Uranium 2 samples
Radon 2 samples
No private-well PFAS data for Hamilton County
We have no private well sampling data for PFAS compounds (PFOA, PFOS, PFNA, and related chemicals) in Hamilton 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 Hamilton County
17Active public water systems
9,009Residents on public water
67%Households on private wells
Public water systems in Hamilton 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 Hamilton 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 Hamilton 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 Hamilton County. Census data explorer →
USGS Aquifer Atlas — principal aquifer type underlying Hamilton 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 Hamilton County, used in contamination risk scoring. TRI Explorer →
EPA Superfund NPL — National Priorities List sites in or near Hamilton 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 FL with at least one sample for that analyte.