Well water in Terrell County, Texas
In Terrell County, none of 60 tested well samples exceeded the EPA limit for fluoride, based on public data from Texas Water Development Board Groundwater Database and USGS Water Quality Portal.
66 individual samples from 25 wells, 1950 to 2023. 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 Terrell 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 1993 to 2023 | 16 | 88% | 13% | 4.55 | 17 | 15 pCi/L EPA limit | |
| Fluoride 1950 to 2023 | 60 | 98% | 0% | 0.912 | 2.5 | 4 mg/L EPA limit | |
| Nitrate 1993 to 2023 | 56 | 100% | 0% | 1.7 | 5.9 | 10 mg/L EPA limit | |
| Lead 1993 to 2023 | 53 | 17% | 0% | 0 | 10 | 15 ug/L EPA limit | |
| Arsenic 1993 to 2023 | 53 | 0% | 0% | 0 | 0 | 10 ug/L EPA limit | |
| Copper 1993 to 2023 | 53 | 60% | 0% | 0.001 | 0.015 | 1.3 mg/L EPA limit | |
| Uranium 2011 to 2023 | 18 | 100% | 0% | 3 | 3.91 | 30 ug/L EPA limit | |
| Radium (226 + 228) 2011 to 2023 | 12 | 50% | 0% | 0.145 | 2.7 | 5 pCi/L EPA limit | |
| Chloride 1950 to 2023 | 66 | 100% | no limit | 19.1 | 203 | 250 mg/L nuisance level | |
| Sodium 1950 to 2023 | 58 | 100% | no limit | 19.2 | 178 | 20 mg/L health guideline | |
| Iron 1993 to 2023 | 57 | 30% | no limit | 0 | 514 | 300 ug/L nuisance level | |
| Manganese 1993 to 2023 | 53 | 28% | no limit | 0 | 29.9 | 300 ug/L health guideline |
Sampled fewer than 10 times, too few to summarize: E. coli (2), Radon (2).
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What this means
The contaminants most often above their limit here are gross alpha (13% of 16 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 Terrell County
- Volatile organic compounds (VOCs)12 leaking underground storage tank sites on record locally.
- Gross alpha13% of 16 local samples were above the limit.
- Coliform bacteriaRecommended for every private well, every year.
- RadonMedian local reading is 180 pCi/L.
- ChlorideDetected in 100% of local samples.
- NitrateRecommended for every private well, especially near farms or septic systems.
- FluorideDetected in 98% of local samples.
- CopperDetected in 60% of local samples.
Contamination sources on record in Terrell County
TCEQ records 12 leaking underground storage tank sites in Terrell County, among 13 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.
- 12
- 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
- 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 Terrell 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 Terrell County.
Common questions
Is there arsenic in well water in Terrell County?
Arsenic was detected in 0% of 53 public well samples in Terrell 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 high is radon in well water in Terrell County?
The median radon level across 2 public samples in Terrell County was 180 pCi/L, with a high of 200 pCi/L. New Hampshire recommends treatment above 2,000 pCi/L.
How often should I test a private well in Terrell 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: 549 samples in Terrell 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: 10 samples in Terrell 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: 13 regulated sites located in Terrell 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.