Well water in Ellis County, Texas
In Ellis County, chloride was detected in 100% of 55 tested well samples from Texas Water Development Board Groundwater Database and USGS Water Quality Portal.
55 individual samples from 47 wells, 1965 to 2016. 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 Ellis 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 1965 to 1987 | 26 | 100% | 12% | 1.95 | 7.4 | 4 mg/L EPA limit | |
| Chloride 1965 to 1987 | 55 | 100% | no limit | 88 | 1,540 | 250 mg/L nuisance level | |
| Sodium 1965 to 1987 | 28 | 100% | no limit | 475 | 1,150 | 20 mg/L health guideline |
Sampled fewer than 10 times, too few to summarize: Radium (226 + 228) (2), Uranium (1), E. coli (1), Iron (3), Radon (1).
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What this means
The contaminants most often above their limit here are fluoride (12% of 26 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 Iron 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 Ellis County
- Volatile organic compounds (VOCs)144 leaking underground storage tank sites on record locally.
- Metals panel2 hazardous waste sites on record locally.
- Fluoride12% of 26 local samples were above the limit.
- Coliform bacteriaRecommended for every private well, every year.
- RadonMedian local reading is 500 pCi/L.
- ChlorideDetected in 100% of local samples.
- IronDetected in 100% of local samples.
- NitrateRecommended for every private well, especially near farms or septic systems.
Contamination sources on record in Ellis County
TCEQ records 144 leaking underground storage tank sites and 2 hazardous waste sites in Ellis County, among 164 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.
- 144
- leaking underground storage tank sitesGasoline and heating oil that leaked from tanks move through groundwater as benzene, MTBE and other volatile organic compounds.
- 2
- hazardous waste sitesSolvents, degreasers and metals from industrial sites can travel far in fractured bedrock.
- 18
- lined landfills and transfer facilities
Treatment that fits the local profile
- Fluoride
- Point-of-use reverse osmosis; Activated alumina; Distillation
- Chloride
- Point-of-use reverse osmosis; Distillation
- Iron
- Oxidizing filter whole-house; Water softener (low levels); Aeration plus filtration
Get your Ellis 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 Ellis County.
Common questions
How high is radon in well water in Ellis County?
The median radon level across 1 public samples in Ellis County was 500 pCi/L, with a high of 500 pCi/L. New Hampshire recommends treatment above 2,000 pCi/L.
How often should I test a private well in Ellis 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: 112 samples in Ellis 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: 5 samples in Ellis 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: 164 regulated sites located in Ellis 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.