Data & Methodology — Tarrant County

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

Contaminant Data — All Analytes

1141 well testing events on record, covering 22 analytes. Data spans 1964 to 2016.

Contaminant Samples Years Detection Rate Distribution LowModHigh vs. Limit vs. TX Avg
Sulfate 81 1993–2016 99%
25% of limit ~ typical
Iron 662 1923–2019 75%
47% of limit ↓ 70% below
Manganese 445 1948–2019 49%
60% of limit ~ typical
PFOS municipal 213 2023–2025 15%
118% of limit ~ typical
Chloride 81 1993–2016 99%
21% of limit ↓ 42% below
PFHxS municipal 213 2023–2025 19%
82% of limit ↑ 86% above
PFOA municipal 213 2023–2025 7%
122% of limit ~ typical
Nitrate 133 1982–2016 68%
4% of limit ↓ 80% below
Uranium 160 1993–2019 51%
7% of limit ↓ 55% below
Fluoride 983 1938–2019 98%
25% of limit ~ typical
Arsenic 264 1982–2019 18%
8% of limit ↓ 78% below
Lead 266 1982–2019 15%
13% of limit ↓ 21% below
HFPO-DA (GenX) municipal 213 2023–2025 0%
— —
Nitrite 80 1993–2016 20%
2% of limit ↑ 138% above
PFNA municipal 213 2023–2025 0%
— —
Radon 1 2016 100%
75% of limit ↑ 107% above
E. coli 1 2016 0%
— —
Hardness 81 1993–2016 99%
— ↑ 60% above
PFBS municipal 213 2023–2025 35%
— ~ typical
pH 82 1993–2016 100%
— ~ typical
Sodium 81 1993–2016 99%
— ↓ 52% below
Total Coliform 1 2016 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 TX.

Compare your result with Tarrant County

Of the 264 arsenic tests on record for Tarrant County (1982–2019), 82% found none.

Of the 81 chloride tests on record for Tarrant County (1993–2016), 1% found none, and half were below 49 mg/L.

Of the 983 fluoride tests on record for Tarrant County (1938–2019), 2% found none, and half were below 900 µg/L.

Of the 662 iron tests on record for Tarrant County (1923–2019), 25% found none, and half were below 100 µg/L.

Of the 266 lead tests on record for Tarrant County (1982–2019), 85% found none.

Of the 445 manganese tests on record for Tarrant County (1948–2019), 51% found none.

Of the 133 nitrate tests on record for Tarrant County (1982–2016), 32% found none, and half were below 60 µg/L.

Of the 81 sulfate tests on record for Tarrant County (1993–2016), 1% found none, and half were below 61 mg/L.

Of the 160 uranium tests on record for Tarrant County (1993–2019), 49% found none, and half were below 0.346 µg/L.

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Data Coverage & Gaps

Well-sampled analytes (15+ samples)

  • Sulfate 81 samples
  • Iron 662 samples
  • Manganese 445 samples
  • Chloride 81 samples
  • Nitrate 133 samples
  • Uranium 160 samples
  • Fluoride 983 samples
  • Arsenic 264 samples
  • Lead 266 samples
  • Nitrite 80 samples
  • Hardness 81 samples
  • pH 82 samples
  • Sodium 81 samples

Limited data (<15 samples) — interpret with caution

  • Radon 1 sample
  • E. coli 1 sample
  • Total Coliform 1 sample

No private-well PFAS data for Tarrant County

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

112 Active public water systems
2,111,952 Residents on public water
0% Households on private wells

Public water systems in Tarrant 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 Tarrant 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 Tarrant County Prevalence TX Average Source Year
Arsenic Cancer prevalence 5.5% 6.1% 2020
Arsenic Kidney disease rate 2.8% 3.3% 2020
Lead Heart disease rate 5.6% 7.4% 2020

Source: CDC PLACES county-level estimates. Raw data: Download Tarrant 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 TX with at least one sample for that analyte.

Last updated: 2026-08-04

Full methodology →