Data & Methodology — El Paso County

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

Contaminant Data — All Analytes

4558 well testing events on record, covering 20 analytes. Data spans 1973 to 2021.

Contaminant Samples Years Detection Rate Distribution LowModHigh vs. Limit vs. TX Avg
Radon 18 1995–2014 100%
72% of limit ↑ 100% above
Arsenic 473 1978–2018 86%
85% of limit ↑ 123% above
Chloride 376 1974–2016 100%
60% of limit ↑ 68% above
Manganese 739 1959–2018 73%
60% of limit ~ typical
Iron 964 1937–2018 83%
20% of limit ↓ 87% below
Sulfate 376 1974–2016 100%
35% of limit ↑ 23% above
Lead 447 1978–2018 36%
27% of limit ↑ 58% above
PFOS municipal 95 2023–2025 3%
212% of limit ↑ 63% above
PFOA municipal 95 2023–2025 1%
728% of limit ↑ 506% above
Nitrate 162 1980–2016 72%
18% of limit ~ typical
Fluoride 4423 1936–2018 100%
18% of limit ↓ 27% below
HFPO-DA (GenX) municipal 95 2023–2025 0%
— —
Nitrite 164 1988–2016 22%
1% of limit ~ typical
PFHxS municipal 95 2023–2025 4%
51% of limit ~ typical
PFNA municipal 95 2023–2025 0%
— —
Uranium 75 1995–2018 83%
9% of limit ↓ 39% below
Hardness 375 1974–2016 100%
— ↓ 35% below
PFBS municipal 95 2023–2025 5%
— ~ typical
pH 395 1974–2016 100%
— ~ typical
Sodium 355 1974–2016 100%
— ↑ 27% above

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 El Paso County

Of the 473 arsenic tests on record for El Paso County (1978–2018), 14% found none, and half were below 7.2 µg/L.

Of the 376 chloride tests on record for El Paso County (1974–2016), 0% found none, and half were below 150 mg/L.

Of the 4423 fluoride tests on record for El Paso County (1936–2018), 0% found none, and half were below 700 µg/L.

Of the 964 iron tests on record for El Paso County (1937–2018), 17% found none, and half were below 40 µg/L.

Of the 447 lead tests on record for El Paso County (1978–2018), 64% found none.

Of the 739 manganese tests on record for El Paso County (1959–2018), 27% found none, and half were below 16 µg/L.

Of the 162 nitrate tests on record for El Paso County (1980–2016), 28% found none, and half were below 1.48 mg/L.

Of the 376 sulfate tests on record for El Paso County (1974–2016), 0% found none, and half were below 87.5 mg/L.

Of the 75 uranium tests on record for El Paso County (1995–2018), 17% found none, and half were below 2.18 µg/L.

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Data Coverage & Gaps

Well-sampled analytes (15+ samples)

  • Radon 18 samples
  • Arsenic 473 samples
  • Chloride 376 samples
  • Manganese 739 samples
  • Iron 964 samples
  • Sulfate 376 samples
  • Lead 447 samples
  • Nitrate 162 samples
  • Fluoride 4423 samples
  • Nitrite 164 samples
  • Uranium 75 samples
  • Hardness 375 samples
  • pH 395 samples
  • Sodium 355 samples

No private-well PFAS data for El Paso County

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

39 Active public water systems
963,345 Residents on public water
2% Households on private wells

Public water systems in El Paso 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 El Paso 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 El Paso County Prevalence TX Average Source Year
Lead Heart disease rate 6.2% 7.4% 2020
Arsenic Cancer prevalence 4.4% 6.1% 2020
Arsenic Kidney disease rate 3.4% 3.3% 2020

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