Well water in Parker County, Texas
In Parker County, 1% of 85 tested well samples exceeded the EPA limit for fluoride (4 mg/L), based on public data from Texas Water Development Board Groundwater Database and USGS Water Quality Portal.
178 individual samples from 135 wells, 1949 to 2019. 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 Parker 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 | |
|---|---|---|---|---|---|---|---|
| Radium (226 + 228) 1989 to 2011 | 12 | 58% | 8% | 0.435 | 5.2 | 5 pCi/L EPA limit | |
| Arsenic 1949 to 2019 | 21 | 10% | 5% | 0 | 250 | 10 ug/L EPA limit | |
| Fluoride 1949 to 2019 | 85 | 98% | 1% | 0.3 | 4.1 | 4 mg/L EPA limit | |
| Nitrate 1994 to 2019 | 31 | 87% | 0% | 0.193 | 7.56 | 10 mg/L EPA limit | |
| Uranium 1994 to 2019 | 21 | 57% | 0% | 1 | 7 | 30 ug/L EPA limit | |
| Lead 1989 to 2019 | 20 | 10% | 0% | 0 | 5 | 15 ug/L EPA limit | |
| Copper 1989 to 2019 | 20 | 55% | 0% | 0.002 | 0.014 | 1.3 mg/L EPA limit | |
| Chloride 1949 to 2019 | 178 | 99% | no limit | 32 | 3,010 | 250 mg/L nuisance level | |
| Sodium 1949 to 2019 | 173 | 100% | no limit | 75 | 2,550 | 20 mg/L health guideline | |
| Iron 1949 to 2019 | 77 | 75% | no limit | 480 | 94,000 | 300 ug/L nuisance level | |
| Manganese 1983 to 2019 | 22 | 50% | no limit | 0.015 | 44 | 300 ug/L health guideline |
Sampled fewer than 10 times, too few to summarize: Gross alpha (7).
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What this means
The contaminants most often above their limit here are radium (226 + 228) (8% of 12 samples), arsenic (5% of 21 samples), and fluoride (1% of 85 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 Parker County
- Volatile organic compounds (VOCs)109 leaking underground storage tank sites on record locally.
- Metals panel1 hazardous waste site on record locally.
- Radium (226 + 228)8% of 12 local samples were above the limit.
- Arsenic5% of 21 local samples were above the limit.
- Fluoride1% of 85 local samples were above the limit.
- Coliform bacteriaRecommended for every private well, every year.
- NitrateRecommended for every private well, especially near farms or septic systems.
- ChlorideDetected in 99% of local samples.
- IronDetected in 75% of local samples.
Contamination sources on record in Parker County
TCEQ records 109 leaking underground storage tank sites and 1 hazardous waste site in Parker County, among 118 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.
- 109
- leaking underground storage tank sitesGasoline and heating oil that leaked from tanks move through groundwater as benzene, MTBE and other volatile organic compounds.
- 1
- hazardous waste siteSolvents, degreasers and metals from industrial sites can travel far in fractured bedrock.
- 8
- lined landfills and transfer facilities
Treatment that fits the local profile
- Radium (226 + 228)
- Water softener (cation exchange); Point-of-use reverse osmosis
- Arsenic
- Point-of-use reverse osmosis; Adsorptive media (iron-based) whole-house; Anion exchange
- 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 Parker 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 Parker County.
Common questions
Is there arsenic in well water in Parker County?
Arsenic was detected in 10% of 21 public well samples in Parker County, and 5% 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 Parker 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: 657 samples in Parker 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 Parker 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: 118 regulated sites located in Parker 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.