Well water in Coryell County, Texas
In Coryell County, 22% of 51 tested well samples exceeded the EPA limit for fluoride (4 mg/L), based on public data from Texas Water Development Board Groundwater Database.
52 individual samples from 27 wells, 1943 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 Coryell 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 | |
|---|---|---|---|---|---|---|---|
| Fluoride 1943 to 2025 | 51 | 100% | 22% | 2.8 | 8.4 | 4 mg/L EPA limit | |
| Chloride 1943 to 2025 | 52 | 100% | no limit | 276 | 4,020 | 250 mg/L nuisance level | |
| Sodium 1943 to 2025 | 51 | 100% | no limit | 510 | 2,500 | 20 mg/L health guideline | |
| Iron 1943 to 2025 | 14 | 43% | no limit | 0 | 2,800 | 300 ug/L nuisance level |
Sampled fewer than 10 times, too few to summarize: Nitrate (8), Arsenic (8), Lead (8), Copper (8), Uranium (3), Radium (226 + 228) (2), Gross alpha (2), Manganese (8).
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What this means
The contaminants most often above their limit here are fluoride (22% of 51 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 Coryell County
- Volatile organic compounds (VOCs)46 leaking underground storage tank sites on record locally.
- Fluoride22% of 51 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.
- CopperDetected in 75% of local samples.
Contamination sources on record in Coryell County
TCEQ records 46 leaking underground storage tank sites in Coryell County, among 57 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.
- 46
- leaking underground storage tank sitesGasoline and heating oil that leaked from tanks move through groundwater as benzene, MTBE and other volatile organic compounds.
- 11
- lined landfills and transfer facilities
Treatment that fits the local profile
- Fluoride
- Point-of-use reverse osmosis; Activated alumina; Distillation
- Copper
- Neutralizing filter to raise pH; Point-of-use reverse osmosis
- Chloride
- Point-of-use reverse osmosis; Distillation
Get your Coryell 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 Coryell County.
Common questions
Is there arsenic in well water in Coryell County?
Arsenic was detected in 63% of 8 public well samples in Coryell 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 Coryell 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: 215 samples in Coryell 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: 57 regulated sites located in Coryell 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.