Well water in Smith County, Texas
In Smith County, none of 52 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.
53 individual samples from 29 wells, 1954 to 2015. 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 Smith 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 | |
|---|---|---|---|---|---|---|---|
| Lead 1978 to 2014 | 14 | 29% | 7% | 0 | 16.5 | 15 ug/L EPA limit | |
| Fluoride 1954 to 2014 | 52 | 90% | 0% | 0.1 | 0.6 | 4 mg/L EPA limit | |
| Arsenic 1978 to 2014 | 14 | 7% | 0% | 0 | 6.2 | 10 ug/L EPA limit | |
| Copper 1984 to 2015 | 14 | 64% | 0% | 0.007 | 0.17 | 1.3 mg/L EPA limit | |
| Nitrate 1992 to 2014 | 11 | 73% | 0% | 0.123 | 6.61 | 10 mg/L EPA limit | |
| Chloride 1954 to 2014 | 53 | 100% | no limit | 9.5 | 43 | 250 mg/L nuisance level | |
| Sodium 1954 to 2014 | 53 | 100% | no limit | 37 | 219 | 20 mg/L health guideline | |
| Iron 1954 to 2014 | 51 | 86% | no limit | 100 | 23,000 | 300 ug/L nuisance level | |
| Manganese 1954 to 2014 | 18 | 83% | no limit | 5.48 | 150 | 300 ug/L health guideline |
Sampled fewer than 10 times, too few to summarize: Radium (226 + 228) (7), Uranium (4), Gross alpha (3), E. coli (2), Radon (2).
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What this means
The contaminants most often above their limit here are lead (7% of 14 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, Iron, and Manganese 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 Smith County
- Volatile organic compounds (VOCs)320 leaking underground storage tank sites on record locally.
- Lead7% of 14 local samples were above the limit.
- Coliform bacteriaRecommended for every private well, every year.
- RadonMedian local reading is 108 pCi/L.
- ChlorideDetected in 100% of local samples.
- NitrateRecommended for every private well, especially near farms or septic systems.
- FluorideDetected in 90% of local samples.
- IronDetected in 86% of local samples.
Contamination sources on record in Smith County
TCEQ records 320 leaking underground storage tank sites in Smith County, among 339 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.
- 320
- leaking underground storage tank sitesGasoline and heating oil that leaked from tanks move through groundwater as benzene, MTBE and other volatile organic compounds.
- 19
- lined landfills and transfer facilities
Treatment that fits the local profile
- Lead
- Point-of-use reverse osmosis; Certified lead-removal carbon filter; Neutralizing filter to raise pH and stop leaching
- 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
- Iron
- Oxidizing filter whole-house; Water softener (low levels); Aeration plus filtration
Get your Smith 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 Smith County.
Common questions
Is there arsenic in well water in Smith County?
Arsenic was detected in 7% of 14 public well samples in Smith 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 Smith County?
The median radon level across 2 public samples in Smith County was 108 pCi/L, with a high of 164 pCi/L. New Hampshire recommends treatment above 2,000 pCi/L.
How often should I test a private well in Smith 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: 287 samples in Smith 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: 11 samples in Smith 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: 339 regulated sites located in Smith 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.