Full contaminant data, sample history, and sourcing for Columbia County. For readers who want to go beyond the summary.
Contaminant Data — All Analytes
517 well testing events on record, covering
23 analytes.
Data spans 1956 to 2023.
Contaminant
Samples
Years
Detection Rate
Distribution LowModHigh
vs. Limit
vs. FL Avg
Iron
195
1976–2025
99%
23% of limit
↓ 88% below
Manganese
195
1976–2025
97%
7% of limit
↓ 75% below
Arsenic
193
1976–2025
98%
5% of limit
↓ 62% below
Chloride
505
1976–2025
100%
2% of limit
↓ 95% below
PFNA
municipal
2
2024–2025
0%
—
—
PFOA
municipal
2
2024–2025
0%
—
—
Fluoride
504
1976–2025
100%
3% of limit
↓ 61% below
HFPO-DA (GenX)
municipal
2
2024–2025
0%
—
—
Nitrite
37
1976–2002
32%
1% of limit
~ typical
Sulfate
504
1976–2025
100%
1% of limit
↓ 95% below
Lead
193
1976–2025
88%
2% of limit
↓ 22% below
Nitrate
37
1976–2002
97%
0% of limit
↓ 100% below
PFHxS
municipal
2
2024–2025
0%
—
—
PFOS
municipal
2
2024–2025
0%
—
—
Radon
1
2002
100%
9% of limit
↓ 69% below
Uranium
23
1976–2002
70%
1% of limit
↓ 27% below
pH
501
1976–2025
100%
—
~ typical
Hardness
42
1976–2013
100%
—
~ typical
Total Coliform
63
2013–2025
100%
—
~ typical
E. coli
26
2021–2025
100%
—
~ typical
Fecal Coliform
37
2013–2021
100%
—
~ typical
PFBS
municipal
2
2024–2025
0%
—
—
Sodium
504
1976–2025
100%
—
↓ 94% 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 Columbia County
Of the 193 arsenic tests on record for Columbia County (1976–2025),
2% found none, and half were below 0.5 µg/L.
Of the 505 chloride tests on record for Columbia County (1976–2025),
0% found none, and half were below 5.7 mg/L.
Of the 504 fluoride tests on record for Columbia County (1976–2025),
0% found none, and half were below 110 µg/L.
Of the 195 iron tests on record for Columbia County (1976–2025),
1% found none, and half were below 70 µg/L.
Of the 193 lead tests on record for Columbia County (1976–2025),
12% found none, and half were below 0.282 µg/L.
Of the 195 manganese tests on record for Columbia County (1976–2025),
3% found none, and half were below 3.12 µg/L.
Of the 37 nitrate tests on record for Columbia County (1976–2002),
3% found none.
Of the 504 sulfate tests on record for Columbia County (1976–2025),
0% found none, and half were below 3.1 mg/L.
Of the 23 uranium tests on record for Columbia County (1976–2002),
30% found none, and half were below 0.17 µg/L.
Data Coverage & Gaps
Well-sampled analytes (15+ samples)
Iron 195 samples
Manganese 195 samples
Arsenic 193 samples
Chloride 505 samples
Fluoride 504 samples
Nitrite 37 samples
Sulfate 504 samples
Lead 193 samples
Nitrate 37 samples
Uranium 23 samples
pH 501 samples
Hardness 42 samples
Total Coliform 63 samples
E. coli 26 samples
Fecal Coliform 37 samples
Sodium 504 samples
Limited data (<15 samples) — interpret with caution
Radon 1 sample
No private-well PFAS data for Columbia County
We have no private well sampling data for PFAS compounds (PFOA, PFOS, PFNA, and related chemicals) in Columbia 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 Columbia County
70Active public water systems
28,292Residents on public water
69%Households on private wells
Public water systems in Columbia 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 Columbia 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 Columbia 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 Columbia County. Census data explorer →
USGS Aquifer Atlas — principal aquifer type underlying Columbia 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 Columbia County, used in contamination risk scoring. TRI Explorer →
EPA Superfund NPL — National Priorities List sites in or near Columbia 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.