Well water in Galveston County, Texas
In Galveston 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 29 wells, 1939 to 2024. 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 Galveston 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 | |
|---|---|---|---|---|---|---|---|
| Chloride 1939 to 2003 | 55 | 100% | no limit | 70 | 5,680 | 250 mg/L nuisance level | |
| Sodium 1939 to 1966 | 20 | 100% | no limit | 218 | 1,150 | 20 mg/L health guideline |
Sampled fewer than 10 times, too few to summarize: Radium (226 + 228) (4), Fluoride (4), Uranium (3), E. coli (2), PFOA (1), PFOS (1), Radon (2).
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What this means
Among contaminants with a federal limit, no tested sample in Galveston County came back above it. That is reassuring, but sampling is uneven: wells that were never tested are not in this data.
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 Galveston County
- Volatile organic compounds (VOCs)357 leaking underground storage tank sites on record locally.
- Metals panel4 hazardous waste sites on record locally.
- Coliform bacteriaRecommended for every private well, every year.
- RadonMedian local reading is 214 pCi/L.
- FluorideDetected in 100% of local samples.
- ChlorideDetected in 100% of local samples.
- NitrateRecommended for every private well, especially near farms or septic systems.
Contamination sources on record in Galveston County
TCEQ records 357 leaking underground storage tank sites and 4 hazardous waste sites in Galveston County, among 376 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.
- 357
- leaking underground storage tank sitesGasoline and heating oil that leaked from tanks move through groundwater as benzene, MTBE and other volatile organic compounds.
- 4
- hazardous waste sitesSolvents, degreasers and metals from industrial sites can travel far in fractured bedrock.
- 15
- 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
Get your Galveston 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 Galveston County.
Common questions
How high is radon in well water in Galveston County?
The median radon level across 2 public samples in Galveston County was 214 pCi/L, with a high of 230 pCi/L. New Hampshire recommends treatment above 2,000 pCi/L.
How often should I test a private well in Galveston 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: 76 samples in Galveston 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: 16 samples in Galveston 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: 376 regulated sites located in Galveston 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.