Well water in Culberson County, Texas
In Culberson County, 8% of 38 tested well samples exceeded the EPA limit for arsenic (10 ug/L), based on public data from Texas Water Development Board Groundwater Database and USGS Water Quality Portal.
76 individual samples from 27 wells, 1943 to 2026. Data refreshed September 9, 2026.
TWDB samples an ambient monitoring network of wells on a rotation, so these describe aquifers, not a survey of homeowners' tests.
What individual samples found
Each row summarizes every public sample for that contaminant inside Culberson County. Above limit means above the EPA maximum contaminant level; where EPA has no enforceable limit, the row shows a health guideline or nuisance level instead.
| Contaminant | Samples | Detected | Above limit | Median | Highest | Limit | |
|---|---|---|---|---|---|---|---|
| Gross alpha 1992 to 2026 | 16 | 88% | 13% | 5.43 | 17.2 | 15 pCi/L EPA limit | |
| Arsenic 1992 to 2026 | 38 | 47% | 8% | 0 | 11.8 | 10 ug/L EPA limit | |
| Nitrate 1980 to 2026 | 40 | 93% | 3% | 2.83 | 12.1 | 10 mg/L EPA limit | |
| Fluoride 1960 to 2026 | 67 | 100% | 1% | 1.2 | 4.12 | 4 mg/L EPA limit | |
| Copper 1992 to 2026 | 38 | 53% | 0% | 0.001 | 0.011 | 1.3 mg/L EPA limit | |
| Lead 1992 to 2026 | 38 | 3% | 0% | 0 | 1.4 | 15 ug/L EPA limit | |
| Uranium 2009 to 2026 | 14 | 100% | 0% | 4.69 | 13.4 | 30 ug/L EPA limit | |
| Chloride 1943 to 2026 | 76 | 99% | no limit | 100 | 740 | 250 mg/L nuisance level | |
| Sodium 1950 to 2026 | 73 | 100% | no limit | 107 | 483 | 20 mg/L health guideline | |
| Iron 1968 to 2026 | 44 | 39% | no limit | 0 | 1,220 | 300 ug/L nuisance level | |
| Manganese 1980 to 2026 | 43 | 63% | no limit | 1.55 | 110 | 300 ug/L health guideline |
Sampled fewer than 10 times, too few to summarize: Radium (226 + 228) (8).
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What this means
The contaminants most often above their limit here are gross alpha (13% of 16 samples), arsenic (8% of 38 samples), and nitrate (3% of 40 samples). A well next door can differ sharply from yours because bedrock fractures, well depth and plumbing all matter, so these rates describe the area, not your tap.
Chloride and Manganese are widespread in local groundwater. They are mainly a staining and taste problem, but high manganese also carries a health advisory for infants.
What to test for in Culberson County
- Volatile organic compounds (VOCs)13 leaking underground storage tank sites on record locally.
- Gross alpha13% of 16 local samples were above the limit.
- Arsenic8% of 38 local samples were above the limit.
- Nitrate3% of 40 local samples were above the limit.
- Fluoride1% of 67 local samples were above the limit.
- Coliform bacteriaRecommended for every private well, every year.
- ChlorideDetected in 99% of local samples.
- ManganeseDetected in 63% of local samples.
Contamination sources on record in Culberson County
TCEQ records 13 leaking underground storage tank sites in Culberson County, among 14 regulated sites in total. Groundwater does not follow property lines, so a well within a few hundred feet of one of these is worth testing for what that site could release.
- 13
- leaking underground storage tank sitesGasoline and heating oil that leaked from tanks move through groundwater as benzene, MTBE and other volatile organic compounds.
- 1
- lined landfill or transfer facility
Treatment that fits the local profile
- Gross alpha
- Point-of-use reverse osmosis; Water softener (cation exchange) for radium; Anion exchange for uranium
- Arsenic
- Point-of-use reverse osmosis; Adsorptive media (iron-based) whole-house; Anion exchange
- Nitrate
- Point-of-use reverse osmosis; Anion exchange; Distillation
- Fluoride
- Point-of-use reverse osmosis; Activated alumina; Distillation
- Copper
- Neutralizing filter to raise pH; Point-of-use reverse osmosis
Get your Culberson County water tested at home
A licensed local water treatment company tests your tap water in your home, walks you through the numbers, and quotes treatment only if something needs fixing. Free, about 30 minutes, no obligation. Tell us what you need and we match you with a company that serves Culberson County.
Common questions
Is there arsenic in well water in Culberson County?
Arsenic was detected in 47% of 38 public well samples in Culberson County, and 8% were above the EPA limit of 10 ug/L. Arsenic has no taste or smell; a lab test is the only way to know your level.
How often should I test a private well in Culberson County?
Test for bacteria and nitrate every year. Test once for arsenic, uranium, radon, fluoride, manganese and PFAS, then again every three to five years or after any change in taste, color, or plumbing.
Sources
- Texas Water Development Board Groundwater Database: 493 samples in Culberson County. Water quality samples from the Texas Water Development Board Groundwater Database, collected by TWDB, groundwater conservation districts and cooperators. Retrieved September 9, 2026.
- USGS Water Quality Portal: 2 samples in Culberson County. Data from the Water Quality Portal, a service of USGS, EPA and USDA; groundwater samples collected by USGS and cooperators. Retrieved September 3, 2026.
- TCEQ regulated sites: 14 regulated sites located in Culberson County. Leaking petroleum storage tank sites, state Superfund sites and municipal solid waste landfills from the Texas Commission on Environmental Quality. Retrieved September 9, 2026.
Non-detects count as samples and are treated as zero when computing medians. Exactly at the limit counts as not above it. A sample belongs to the town containing the well's reported coordinates.