Data & Methodology — Stonewall County

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

Contaminant Data — All Analytes

129 well testing events on record, covering 12 analytes. Data spans 1959 to 2014.

Contaminant Samples Years Detection Rate Distribution LowModHigh vs. Limit vs. TX Avg
Sulfate 58 1978–1980 100%
880% of limit ↑ 2985% above
Chloride 58 1978–1980 100%
1420% of limit ↑ 3869% above
Nitrate 5 1990 100%
90% of limit ↑ 303% above
Manganese 20 1990–2015 55%
320% of limit ↑ 397% above
Lead 20 1990–2015 35%
1567% of limit ↑ 9189% above
Iron 20 1990–2015 55%
24% of limit ↓ 84% below
Fluoride 107 1961–2015 96%
15% of limit ↓ 37% below
Arsenic 20 1990–2015 50%
45% of limit ~ typical
Uranium 2 2015 100%
60% of limit ↑ 288% above
Hardness 38 1978–1979 100%
— ↑ 1132% above
pH 38 1978–1979 100%
— ~ typical
Sodium 38 1978–1979 100%
— ↑ 1991% 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 Stonewall County

Of the 20 arsenic tests on record for Stonewall County (1990–2015), 50% found none, and half were below 1.5 µg/L.

Of the 58 chloride tests on record for Stonewall County (1978–1980), 0% found none, and half were below 3550 mg/L.

Of the 107 fluoride tests on record for Stonewall County (1961–2015), 4% found none, and half were below 600 µg/L.

Of the 20 iron tests on record for Stonewall County (1990–2015), 45% found none, and half were below 22.5 µg/L.

Of the 20 lead tests on record for Stonewall County (1990–2015), 65% found none.

Of the 20 manganese tests on record for Stonewall County (1990–2015), 45% found none, and half were below 2.35 µg/L.

Of the 58 sulfate tests on record for Stonewall County (1978–1980), 0% found none, and half were below 2200 mg/L.

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Data Coverage & Gaps

Well-sampled analytes (15+ samples)

  • Sulfate 58 samples
  • Chloride 58 samples
  • Manganese 20 samples
  • Lead 20 samples
  • Iron 20 samples
  • Fluoride 107 samples
  • Arsenic 20 samples
  • Hardness 38 samples
  • pH 38 samples
  • Sodium 38 samples

Limited data (<15 samples) — interpret with caution

  • Nitrate 5 samples
  • Uranium 2 samples

No private-well PFAS data for Stonewall County

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

3 Active public water systems
956 Residents on public water
18% Households on private wells

Public water systems in Stonewall 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 Stonewall 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 Stonewall County Prevalence TX Average Source Year
Nitrate Cancer prevalence 5.8% 6.1% 2020
Lead Heart disease rate 10.8% 7.4% 2020

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