Data & Methodology — DeSoto County Well Water

Contaminant Data — All Analytes

1372 well testing events on record, covering 22 analytes. Data spans 1930 to 2023.

Contaminant	Samples	Years	Detection Rate	vs. Limit	vs. FL Avg
PFOA municipal	19	2024–2025	37%	122% of limit	~ typical
Sulfate	1320	1950–2025	100%	56% of limit	↑ 113% above
PFOS municipal	19	2024–2025	26%	108% of limit	↓ 49% below
Chloride	1342	1950–2025	100%	27% of limit	↓ 45% below
Iron	1155	1950–2025	99%	3% of limit	↓ 99% below
Lead	55	1972–2024	56%	1% of limit	↓ 58% below
Arsenic	56	1972–2024	88%	3% of limit	↓ 80% below
Manganese	1092	1973–2025	98%	1% of limit	↓ 98% below
Uranium	1	1979	100%	0% of limit	↓ 97% below
Fluoride	1129	1950–2025	99%	29% of limit	↑ 308% above
HFPO-DA (GenX) municipal	19	2024–2025	0%	—	—
Nitrite	79	1970–1994	81%	0% of limit	↓ 100% below
Nitrate	86	1962–1994	95%	0% of limit	↓ 100% below
PFHxS municipal	19	2024–2025	0%	—	—
PFNA municipal	19	2024–2025	0%	—	—
pH	1038	1950–2025	100%	—	~ typical
Sodium	1260	1950–2025	100%	—	↓ 40% below
Hardness	194	1950–1997	100%	—	↑ 51% above
Total Coliform	49	1972–2024	100%	—	~ typical
E. coli	19	2021–2024	100%	—	~ typical
Fecal Coliform	29	1972–2021	98%	—	~ typical
PFBS municipal	19	2024–2025	79%	—	~ 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 FL.

Data Coverage & Gaps

Well-sampled analytes (15+ samples)

Sulfate 1320 samples
Chloride 1342 samples
Iron 1155 samples
Lead 55 samples
Arsenic 56 samples
Manganese 1092 samples
Fluoride 1129 samples
Nitrite 79 samples
Nitrate 86 samples
pH 1038 samples
Sodium 1260 samples
Hardness 194 samples
Total Coliform 49 samples
E. coli 19 samples
Fecal Coliform 29 samples

Limited data (<15 samples) — interpret with caution

Uranium 1 sample

No private-well PFAS data for DeSoto County

We have no private well sampling data for PFAS compounds (PFOA, PFOS, PFNA, and related chemicals) in DeSoto County. PFAS has been detected in local public water systems (UCMR 5 data) — indicated by the "municipal" badge in the table above — but this does not directly indicate private well contamination. 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 DeSoto County

40 Active public water systems

26,510 Residents on public water

Public water systems in DeSoto 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 DeSoto 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.

Contaminant	Associated Condition	DeSoto County Prevalence	FL Average	Source Year
Arsenic	Cancer prevalence	7.5%	6.8%	2020
Arsenic	Kidney disease rate	3.7%	3.4%	2020
Lead	Heart disease rate	10.7%	7.7%	2020

Data Sources

This report aggregates data from the following public databases:

Water Quality Portal (WQP) — groundwater sample results for DeSoto 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 DeSoto County. Census data explorer →
USGS Aquifer Atlas — principal aquifer type underlying DeSoto 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 DeSoto County, used in contamination risk scoring. TRI Explorer →
EPA Superfund NPL — National Priorities List sites in or near DeSoto 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.

Last updated: 2026-08-12

Full methodology →