Data & Methodology — Pinellas County

Full contaminant data, sample history, and sourcing for Pinellas County. For readers who want to go beyond the summary.

Contaminant Data — All Analytes

5865 well testing events on record, covering 22 analytes. Data spans 1917 to 2025.

Contaminant Samples Years Detection Rate Distribution LowModHigh vs. Limit vs. FL Avg
Iron 896 1917–2025 98%
402% of limit ↑ 99% above
Chloride 5280 1949–2025 100%
136% of limit ↑ 178% above
Sulfate 1402 1949–2025 99%
18% of limit ↓ 30% below
Manganese 437 1971–2025 95%
43% of limit ↑ 61% above
PFOS municipal 64 2023–2025 9%
840% of limit ↑ 298% above
Arsenic 1145 1971–2024 80%
30% of limit ↑ 130% above
PFOA municipal 64 2023–2025 8%
242% of limit ↑ 70% above
Nitrate 1760 1949–2002 97%
0% of limit ↓ 94% below
Lead 788 1917–2024 11%
0% of limit ↓ 100% below
Fluoride 757 1949–2025 94%
6% of limit ↓ 23% below
Nitrite 1798 1971–2022 56%
1% of limit ~ typical
HFPO-DA (GenX) municipal 64 2023–2025 0%
— —
PFHxS municipal 64 2023–2025 6%
76% of limit ↑ 47% above
PFNA municipal 64 2023–2025 0%
— —
Uranium 2 2002 50%
0% of limit ↓ 96% below
E. coli 7 2002–2024 100%
— ~ typical
Fecal Coliform 10 1973–2021 33%
— ~ typical
Hardness 1607 1949–2002 100%
— ↑ 42% above
PFBS municipal 64 2023–2025 11%
— ~ typical
pH 2297 1949–2025 100%
— ~ typical
Sodium 1874 1917–2025 100%
— ↑ 25% above
Total Coliform 17 1973–2024 60%
— ~ 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.

Compare your result with Pinellas County

Of the 1145 arsenic tests on record for Pinellas County (1971–2024), 20% found none, and half were below 2 µg/L.

Of the 5280 chloride tests on record for Pinellas County (1949–2025), 0% found none, and half were below 340 mg/L.

Of the 757 fluoride tests on record for Pinellas County (1949–2025), 6% found none, and half were below 200 µg/L.

Of the 896 iron tests on record for Pinellas County (1917–2025), 2% found none, and half were below 1.2 mg/L.

Of the 788 lead tests on record for Pinellas County (1917–2024), 89% found none.

Of the 437 manganese tests on record for Pinellas County (1971–2025), 5% found none, and half were below 20 µg/L.

Of the 1760 nitrate tests on record for Pinellas County (1949–2002), 3% found none, and half were below 10 µg/L.

Of the 1402 sulfate tests on record for Pinellas County (1949–2025), 1% found none, and half were below 45.7 mg/L.

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Data Coverage & Gaps

Well-sampled analytes (15+ samples)

  • Iron 896 samples
  • Chloride 5280 samples
  • Sulfate 1402 samples
  • Manganese 437 samples
  • Arsenic 1145 samples
  • Nitrate 1760 samples
  • Lead 788 samples
  • Fluoride 757 samples
  • Nitrite 1798 samples
  • Hardness 1607 samples
  • pH 2297 samples
  • Sodium 1874 samples
  • Total Coliform 17 samples

Limited data (<15 samples) — interpret with caution

  • Uranium 2 samples
  • E. coli 7 samples
  • Fecal Coliform 10 samples

No private-well PFAS data for Pinellas County

We have no private well sampling data for PFAS compounds (PFOA, PFOS, PFNA, and related chemicals) in Pinellas 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 Pinellas County

13 Active public water systems
1,147,926 Residents on public water
1% Households on private wells

Public water systems in Pinellas 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 Pinellas 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 Pinellas County Prevalence FL Average Source Year
Arsenic Cancer prevalence 8.6% 6.8% 2020
Arsenic Kidney disease rate 3.7% 3.4% 2020
Lead Heart disease rate 5.8% 7.7% 2020

Source: CDC PLACES county-level estimates. Raw data: Download Pinellas County CDC PLACES data →

Data Sources

This report aggregates data from the following public databases:

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 →