Well water in Colorado County, Texas
In Colorado County, 8% of 37 tested well samples exceeded the EPA limit for radium (226 + 228) (5 pCi/L), based on public data from Texas Water Development Board Groundwater Database.
97 individual samples from 39 wells, 1937 to 2025. 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 Colorado 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 | |
|---|---|---|---|---|---|---|---|
| Radium (226 + 228) 2006 to 2020 | 37 | 38% | 8% | 0 | 10.1 | 5 pCi/L EPA limit | |
| Gross alpha 1988 to 2025 | 37 | 51% | 5% | 2.7 | 16 | 15 pCi/L EPA limit | |
| Fluoride 1965 to 2025 | 78 | 95% | 0% | 0.405 | 0.86 | 4 mg/L EPA limit | |
| Nitrate 1988 to 2025 | 65 | 72% | 0% | 0.21 | 3.6 | 10 mg/L EPA limit | |
| Arsenic 1988 to 2025 | 62 | 24% | 0% | 0 | 3 | 10 ug/L EPA limit | |
| Copper 1988 to 2025 | 62 | 32% | 0% | 0 | 0.016 | 1.3 mg/L EPA limit | |
| Lead 1988 to 2025 | 57 | 0% | 0% | 0 | 0 | 15 ug/L EPA limit | |
| Uranium 2006 to 2025 | 27 | 52% | 0% | 1 | 11.8 | 30 ug/L EPA limit | |
| Chloride 1937 to 2025 | 97 | 100% | no limit | 102 | 440 | 250 mg/L nuisance level | |
| Sodium 1965 to 2025 | 81 | 100% | no limit | 83.8 | 234 | 20 mg/L health guideline | |
| Iron 1974 to 2025 | 70 | 24% | no limit | 0 | 1,530 | 300 ug/L nuisance level | |
| Manganese 1988 to 2025 | 62 | 44% | no limit | 0 | 17.4 | 300 ug/L health guideline |
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What this means
The contaminants most often above their limit here are radium (226 + 228) (8% of 37 samples) and gross alpha (5% of 37 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 is widespread in local groundwater. It is mainly a staining and taste problem, but high manganese also carries a health advisory for infants.
What to test for in Colorado County
- Volatile organic compounds (VOCs)44 leaking underground storage tank sites on record locally.
- Radium (226 + 228)8% of 37 local samples were above the limit.
- Gross alpha5% of 37 local samples were above the limit.
- Coliform bacteriaRecommended for every private well, every year.
- ChlorideDetected in 100% of local samples.
- NitrateRecommended for every private well, especially near farms or septic systems.
- FluorideDetected in 95% of local samples.
Contamination sources on record in Colorado County
TCEQ records 44 leaking underground storage tank sites in Colorado County, among 54 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.
- 44
- leaking underground storage tank sitesGasoline and heating oil that leaked from tanks move through groundwater as benzene, MTBE and other volatile organic compounds.
- 10
- lined landfills and transfer facilities
Treatment that fits the local profile
- Radium (226 + 228)
- Water softener (cation exchange); Point-of-use reverse osmosis
- Gross alpha
- Point-of-use reverse osmosis; Water softener (cation exchange) for radium; Anion exchange for uranium
- Fluoride
- Point-of-use reverse osmosis; Activated alumina; Distillation
- Chloride
- Point-of-use reverse osmosis; Distillation
Get your Colorado 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 Colorado County.
Common questions
Is there arsenic in well water in Colorado County?
Arsenic was detected in 24% of 62 public well samples in Colorado County, and 0% 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 Colorado 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: 735 samples in Colorado County. Water quality samples from the Texas Water Development Board Groundwater Database, collected by TWDB, groundwater conservation districts and cooperators. Retrieved September 9, 2026.
- TCEQ regulated sites: 54 regulated sites located in Colorado 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.