Data & Methodology — Collier County

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

Contaminant Data — All Analytes

6659 well testing events on record, covering 23 analytes. Data spans 1901 to 2022.

Contaminant Samples Years Detection Rate Distribution LowModHigh vs. Limit vs. FL Avg
Radon 5 2015–2019 100%
170% of limit ↑ 480% above
Iron 1002 1923–2024 99%
64% of limit ↓ 68% below
PFOS municipal 22 2023–2025 41%
195% of limit ~ typical
Chloride 6470 1901–2025 100%
20% of limit ↓ 59% below
PFOA municipal 22 2023–2025 14%
105% of limit ↓ 26% below
Sulfate 1289 1901–2025 99%
9% of limit ↓ 67% below
Manganese 849 1955–2024 98%
18% of limit ↓ 30% below
Arsenic 843 1970–2024 96%
6% of limit ↓ 58% below
Uranium 79 1965–2022 85%
2% of limit ↑ 69% above
Nitrate 671 1901–2020 95%
0% of limit ↓ 99% below
Lead 1026 1970–2024 79%
0% of limit ↓ 89% below
Fluoride 1237 1901–2025 99%
5% of limit ↓ 32% below
PFHxS municipal 22 2023–2025 18%
33% of limit ↓ 36% below
PFNA municipal 22 2023–2025 0%
— —
HFPO-DA (GenX) municipal 22 2023–2025 0%
— —
Nitrite 984 1970–2023 90%
0% of limit ↓ 95% below
Hardness 466 1901–2019 100%
— ↑ 42% above
PFBS municipal 22 2023–2025 9%
— ~ typical
Fecal Coliform 89 1976–2021 57%
— ~ typical
E. coli 148 2015–2025 97%
— ~ typical
pH 1470 1901–2025 100%
— ~ typical
Sodium 1351 1901–2025 100%
— ↓ 47% below
Total Coliform 157 1976–2025 66%
— ~ 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 Collier County

Of the 843 arsenic tests on record for Collier County (1970–2024), 4% found none, and half were below 0.496 µg/L.

Of the 6470 chloride tests on record for Collier County (1901–2025), 0% found none, and half were below 50 mg/L.

Of the 1237 fluoride tests on record for Collier County (1901–2025), 1% found none, and half were below 190 µg/L.

Of the 1002 iron tests on record for Collier County (1923–2024), 1% found none, and half were below 172 µg/L.

Of the 1026 lead tests on record for Collier County (1970–2024), 21% found none, and half were below 30 ng/L.

Of the 849 manganese tests on record for Collier County (1955–2024), 2% found none, and half were below 9.03 µg/L.

Of the 671 nitrate tests on record for Collier County (1901–2020), 5% found none, and half were below 2 µg/L.

Of the 1289 sulfate tests on record for Collier County (1901–2025), 1% found none, and half were below 21.8 mg/L.

Of the 79 uranium tests on record for Collier County (1965–2022), 15% found none, and half were below 0.5 µg/L.

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Data Coverage & Gaps

Well-sampled analytes (15+ samples)

  • Iron 1002 samples
  • Chloride 6470 samples
  • Sulfate 1289 samples
  • Manganese 849 samples
  • Arsenic 843 samples
  • Uranium 79 samples
  • Nitrate 671 samples
  • Lead 1026 samples
  • Fluoride 1237 samples
  • Nitrite 984 samples
  • Hardness 466 samples
  • Fecal Coliform 89 samples
  • E. coli 148 samples
  • pH 1470 samples
  • Sodium 1351 samples
  • Total Coliform 157 samples

Limited data (<15 samples) — interpret with caution

  • Radon 5 samples

No private-well PFAS data for Collier County

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

45 Active public water systems
385,870 Residents on public water
17% Households on private wells

Public water systems in Collier 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 Collier 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 Collier County Prevalence FL Average Source Year
Arsenic Cancer prevalence 5.8% 6.8% 2020
Arsenic Kidney disease rate 2.7% 3.4% 2020
Lead Heart disease rate 9.9% 7.7% 2020

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