Data & Methodology — Martin County

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

Contaminant Data — All Analytes

2822 well testing events on record, covering 23 analytes. Data spans 1923 to 2023.

Contaminant Samples Years Detection Rate Distribution LowModHigh vs. Limit vs. FL Avg
Radon 12 2008–2019 100%
105% of limit ↑ 258% above
Iron 151 1923–2024 96%
120% of limit ↓ 40% below
PFOS municipal 12 2023–2025 33%
262% of limit ↑ 24% above
PFOA municipal 12 2023–2025 25%
103% of limit ↓ 28% below
Chloride 2806 1923–2024 100%
13% of limit ↓ 74% below
Sulfate 166 1923–2024 93%
6% of limit ↓ 78% below
Manganese 65 1984–2024 97%
22% of limit ~ typical
Lead 68 1974–2024 79%
1% of limit ↓ 58% below
Arsenic 68 1974–2024 87%
3% of limit ↓ 79% below
PFNA municipal 12 2023–2025 0%
— —
Fluoride 146 1946–2024 97%
8% of limit ~ typical
HFPO-DA (GenX) municipal 12 2023–2025 0%
— —
Nitrite 42 1974–2019 60%
1% of limit ~ typical
Nitrate 71 1923–2019 80%
0% of limit ↓ 94% below
PFHxS municipal 12 2023–2025 17%
62% of limit ↑ 21% above
Uranium 12 2008–2019 58%
0% of limit ↓ 88% below
Hardness 123 1923–2019 99%
— ~ typical
Total Coliform 51 2015–2024 92%
— ~ typical
Sodium 135 1954–2024 100%
— ↓ 46% below
pH 176 1942–2024 100%
— ~ typical
E. coli 22 2015–2024 78%
— ~ typical
Fecal Coliform 29 2017–2021 100%
— ~ typical
PFBS municipal 12 2023–2025 25%
— ~ 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 Martin County

Of the 68 arsenic tests on record for Martin County (1974–2024), 13% found none, and half were below 0.2 µg/L.

Of the 2806 chloride tests on record for Martin County (1923–2024), 0% found none, and half were below 32 mg/L.

Of the 146 fluoride tests on record for Martin County (1946–2024), 3% found none, and half were below 300 µg/L.

Of the 151 iron tests on record for Martin County (1923–2024), 4% found none, and half were below 290 µg/L.

Of the 68 lead tests on record for Martin County (1974–2024), 21% found none, and half were below 0.2 µg/L.

Of the 65 manganese tests on record for Martin County (1984–2024), 3% found none, and half were below 10.5 µg/L.

Of the 71 nitrate tests on record for Martin County (1923–2019), 20% found none, and half were below 10 µg/L.

Of the 166 sulfate tests on record for Martin County (1923–2024), 7% found none, and half were below 12.9 mg/L.

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Data Coverage & Gaps

Well-sampled analytes (15+ samples)

  • Iron 151 samples
  • Chloride 2806 samples
  • Sulfate 166 samples
  • Manganese 65 samples
  • Lead 68 samples
  • Arsenic 68 samples
  • Fluoride 146 samples
  • Nitrite 42 samples
  • Nitrate 71 samples
  • Hardness 123 samples
  • Total Coliform 51 samples
  • Sodium 135 samples
  • pH 176 samples
  • E. coli 22 samples
  • Fecal Coliform 29 samples

Limited data (<15 samples) — interpret with caution

  • Radon 12 samples
  • Uranium 12 samples

No private-well PFAS data for Martin County

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

60 Active public water systems
161,250 Residents on public water
7% Households on private wells

Public water systems in Martin 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 Martin 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 Martin County Prevalence FL Average Source Year
Lead Heart disease rate 5.7% 7.7% 2020
PFOA Cancer prevalence 10.1% 6.8% 2020

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