Well water in McCulloch County, Texas
In McCulloch County, 6% of 33 tested well samples exceeded the EPA limit for nitrate (10 mg/L), based on public data from Texas Water Development Board Groundwater Database.
108 individual samples from 44 wells, 1943 to 2021. 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 McCulloch 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) 1987 to 2020 | 26 | 81% | 46% | 3.99 | 94 | 5 pCi/L EPA limit | |
| Gross alpha 1987 to 2021 | 25 | 92% | 28% | 7.14 | 47 | 15 pCi/L EPA limit | |
| Nitrate 1993 to 2021 | 33 | 52% | 6% | 0.01 | 67.4 | 10 mg/L EPA limit | |
| Fluoride 1943 to 2021 | 106 | 98% | 4% | 0.9 | 6.4 | 4 mg/L EPA limit | |
| Lead 1988 to 2021 | 34 | 12% | 0% | 0 | 3.17 | 15 ug/L EPA limit | |
| Arsenic 1988 to 2021 | 34 | 26% | 0% | 0 | 6.1 | 10 ug/L EPA limit | |
| Copper 1988 to 2021 | 34 | 47% | 0% | 0 | 0.023 | 1.3 mg/L EPA limit | |
| Chloride 1943 to 2021 | 108 | 100% | no limit | 53.3 | 830 | 250 mg/L nuisance level | |
| Sodium 1958 to 2021 | 105 | 100% | no limit | 41.7 | 543 | 20 mg/L health guideline | |
| Iron 1943 to 2021 | 55 | 82% | no limit | 460 | 9,300 | 300 ug/L nuisance level | |
| Manganese 1973 to 2021 | 35 | 83% | no limit | 3.55 | 55.7 | 300 ug/L health guideline |
Sampled fewer than 10 times, too few to summarize: Uranium (7).
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What this means
The contaminants most often above their limit here are radium (226 + 228) (46% of 26 samples), gross alpha (28% of 25 samples), and nitrate (6% of 33 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 McCulloch County
- Volatile organic compounds (VOCs)28 leaking underground storage tank sites on record locally.
- Metals panel1 hazardous waste site on record locally.
- Radium (226 + 228)46% of 26 local samples were above the limit.
- Gross alpha28% of 25 local samples were above the limit.
- Nitrate6% of 33 local samples were above the limit.
- Fluoride4% of 106 local samples were above the limit.
- Coliform bacteriaRecommended for every private well, every year.
- ChlorideDetected in 100% of local samples.
- ManganeseDetected in 83% of local samples.
Contamination sources on record in McCulloch County
TCEQ records 28 leaking underground storage tank sites and 1 hazardous waste site in McCulloch County, among 33 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.
- 28
- 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.
- 4
- lined landfills and transfer facilities
Treatment that fits the local profile
- Radium (226 + 228)
- Water softener (cation exchange); Point-of-use reverse osmosis
- Gross alpha
- Point-of-use reverse osmosis; Water softener (cation exchange) for radium; Anion exchange for uranium
- Nitrate
- Point-of-use reverse osmosis; Anion exchange; Distillation
- Fluoride
- Point-of-use reverse osmosis; Activated alumina; Distillation
- Chloride
- Point-of-use reverse osmosis; Distillation
Get your McCulloch 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 McCulloch County.
Common questions
Is there arsenic in well water in McCulloch County?
Arsenic was detected in 26% of 34 public well samples in McCulloch 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 often should I test a private well in McCulloch 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: 602 samples in McCulloch County. Water quality samples from the Texas Water Development Board Groundwater Database, collected by TWDB, groundwater conservation districts and cooperators. Retrieved September 9, 2026.
- TCEQ regulated sites: 33 regulated sites located in McCulloch 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.