Full contaminant data, sample history, and sourcing for Walton County. For readers who want to go beyond the summary.
Contaminant Data — All Analytes
1386 well testing events on record, covering
23 analytes.
Data spans 1949 to 2025.
Contaminant
Samples
Years
Detection Rate
Distribution LowModHigh
vs. Limit
vs. FL Avg
Radon
3
2009–2015
100%
153% of limit
↑ 423% above
Chloride
1364
1949–2025
100%
36% of limit
↓ 26% below
Iron
106
1949–2025
93%
33% of limit
↓ 83% below
Manganese
79
1950–2025
100%
4% of limit
↓ 83% below
Arsenic
43
1976–2025
100%
6% of limit
↓ 57% below
Sulfate
126
1949–2025
100%
3% of limit
↓ 89% below
PFHxS
municipal
48
2023–2024
0%
—
—
PFOS
municipal
48
2023–2024
0%
—
—
Uranium
3
2009–2015
67%
0% of limit
↓ 68% below
Lead
43
1976–2025
93%
1% of limit
↓ 58% below
Nitrate
87
1949–2015
98%
0% of limit
↓ 100% below
Fluoride
145
1949–2025
100%
5% of limit
↓ 30% below
HFPO-DA (GenX)
municipal
48
2023–2024
0%
—
—
Nitrite
5
1975–2015
0%
—
—
PFOA
municipal
48
2023–2024
0%
—
—
PFNA
municipal
48
2023–2024
0%
—
—
Total Coliform
39
2009–2025
98%
—
~ typical
Hardness
102
1949–2015
100%
—
↓ 57% below
pH
188
1949–2025
100%
—
~ typical
Sodium
135
1957–2025
100%
—
↓ 93% below
E. coli
15
2009–2025
83%
—
~ typical
Fecal Coliform
24
2017–2021
100%
—
~ typical
PFBS
municipal
48
2023–2024
0%
—
—
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 Walton County
Of the 43 arsenic tests on record for Walton County (1976–2025),
0% found none, and half were below 0.56 µg/L.
Of the 1364 chloride tests on record for Walton County (1949–2025),
0% found none, and half were below 90 mg/L.
Of the 145 fluoride tests on record for Walton County (1949–2025),
0% found none, and half were below 200 µg/L.
Of the 106 iron tests on record for Walton County (1949–2025),
7% found none, and half were below 75 µg/L.
Of the 43 lead tests on record for Walton County (1976–2025),
7% found none, and half were below 0.2 µg/L.
Of the 79 manganese tests on record for Walton County (1950–2025),
0% found none, and half were below 2.2 µg/L.
Of the 87 nitrate tests on record for Walton County (1949–2015),
2% found none.
Of the 126 sulfate tests on record for Walton County (1949–2025),
0% found none, and half were below 7.45 mg/L.
Data Coverage & Gaps
Well-sampled analytes (15+ samples)
Chloride 1364 samples
Iron 106 samples
Manganese 79 samples
Arsenic 43 samples
Sulfate 126 samples
Lead 43 samples
Nitrate 87 samples
Fluoride 145 samples
Total Coliform 39 samples
Hardness 102 samples
pH 188 samples
Sodium 135 samples
E. coli 15 samples
Fecal Coliform 24 samples
Limited data (<15 samples) — interpret with caution
Radon 3 samples
Uranium 3 samples
Nitrite 5 samples
No private-well PFAS data for Walton County
We have no private well sampling data for PFAS compounds (PFOA, PFOS, PFNA, and related chemicals) in Walton 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 Walton County
27Active public water systems
124,667Residents on public water
12%Households on private wells
Public water systems in Walton 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 Walton 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 Walton 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 Walton County. Census data explorer →
USGS Aquifer Atlas — principal aquifer type underlying Walton 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 Walton County, used in contamination risk scoring. TRI Explorer →
EPA Superfund NPL — National Priorities List sites in or near Walton 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.