Data & Methodology — Pecos County

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

Contaminant Data — All Analytes

804 well testing events on record, covering 22 analytes. Data spans 1941 to 2017.

Contaminant Samples Years Detection Rate Distribution LowModHigh vs. Limit vs. TX Avg
Radon 3 2017 100%
133% of limit ↑ 270% above
Sulfate 92 1932–2017 100%
155% of limit ↑ 443% above
Chloride 92 1932–2017 100%
131% of limit ↑ 265% above
Iron 467 1932–2021 63%
33% of limit ↓ 79% below
Manganese 443 1942–2021 68%
18% of limit ↓ 72% below
Uranium 138 2007–2021 80%
16% of limit ~ typical
Fluoride 766 1941–2021 99%
35% of limit ↑ 46% above
Arsenic 432 1988–2021 23%
20% of limit ↓ 48% below
Nitrate 144 1987–2017 82%
16% of limit ↓ 29% below
HFPO-DA (GenX) municipal 6 2024 0%
— —
Lead 429 1988–2021 14%
10% of limit ↓ 40% below
Nitrite 65 1987–2017 15%
1% of limit ↓ 27% below
PFHxS municipal 6 2024 0%
— —
PFNA municipal 6 2024 0%
— —
PFOA municipal 6 2024 0%
— —
PFOS municipal 6 2024 0%
— —
E. coli 3 2017 0%
— —
Hardness 92 1932–2017 100%
— ↑ 138% above
PFBS municipal 6 2024 0%
— —
pH 74 1972–2017 100%
— ~ typical
Sodium 88 1932–2017 100%
— ↑ 89% above
Total Coliform 3 2017 33%
— ~ 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 TX.

Compare your result with Pecos County

Of the 432 arsenic tests on record for Pecos County (1988–2021), 77% found none.

Of the 92 chloride tests on record for Pecos County (1932–2017), 0% found none, and half were below 326 mg/L.

Of the 766 fluoride tests on record for Pecos County (1941–2021), 1% found none, and half were below 1.4 mg/L.

Of the 467 iron tests on record for Pecos County (1932–2021), 37% found none, and half were below 22.9 µg/L.

Of the 429 lead tests on record for Pecos County (1988–2021), 86% found none.

Of the 443 manganese tests on record for Pecos County (1942–2021), 32% found none, and half were below 3.31 µg/L.

Of the 144 nitrate tests on record for Pecos County (1987–2017), 18% found none, and half were below 1.19 mg/L.

Of the 92 sulfate tests on record for Pecos County (1932–2017), 0% found none, and half were below 388 mg/L.

Of the 138 uranium tests on record for Pecos County (2007–2021), 20% found none, and half were below 3.95 µg/L.

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Data Coverage & Gaps

Well-sampled analytes (15+ samples)

  • Sulfate 92 samples
  • Chloride 92 samples
  • Iron 467 samples
  • Manganese 443 samples
  • Uranium 138 samples
  • Fluoride 766 samples
  • Arsenic 432 samples
  • Nitrate 144 samples
  • Lead 429 samples
  • Nitrite 65 samples
  • Hardness 92 samples
  • pH 74 samples
  • Sodium 88 samples

Limited data (<15 samples) — interpret with caution

  • Radon 3 samples
  • E. coli 3 samples
  • Total Coliform 3 samples

No private-well PFAS data for Pecos County

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

10 Active public water systems
14,839 Residents on public water
24% Households on private wells

Public water systems in Pecos 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 Pecos 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 Pecos County Prevalence TX Average Source Year
Arsenic Cancer prevalence 4.9% 6.1% 2020
Arsenic Kidney disease rate 3.3% 3.3% 2020

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