Well water in Robertson County, Texas
In Robertson County, 2% of 44 tested well samples exceeded the EPA limit for nitrate (10 mg/L), based on public data from Texas Water Development Board Groundwater Database and USGS Water Quality Portal.
The strongest signal is gross alpha: 8% of 13 local samples were above the limit, too few samples to carry the headline but first on the test list below.
795 test results across 14 contaminants from at least 122 wells, 1940 to 2026; chloride has the most at 158. Data refreshed September 15, 2026.
Compiled by Nick at Well Water Nerd from public records. How these pages are built
TWDB samples an ambient monitoring network of wells on a rotation, so these describe aquifers, not a survey of homeowners' tests.
An estimated 1,382 people in Robertson County get their drinking water from a private well, per USGS 2015 county water use. That is about 8% of residents.
Separately, the USGS national arsenic model estimates that 3% of the 1,382 people on private wells in Robertson County draw water above 10 ug/L (the model's range is 3% to 4%), from geology and well depth rather than local tests.
What individual samples found
Each row summarizes every public sample for that contaminant inside Robertson 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 | Above limit | Samples | Detected | Median | Highest | Limit |
|---|---|---|---|---|---|---|
| Gross alpha 1993 to 2014 | 13 | 38% | 0 | 18.1 | 15 pCi/L EPA limit | |
| Nitrate 1993 to 2026 | 44 | 43% | 0 | 13.4 | 10 mg/L EPA limit | |
| Fluoride 1941 to 2026 | 150 | 90% | 0.2 | 2.8 | 4 mg/L EPA limit | |
| Arsenic 1993 to 2026 | 37 | 14% | 0 | 3.42 | 10 ug/L EPA limit | |
| Copper 1993 to 2026 | 33 | 27% | 0 | 0.005 | 1.3 mg/L EPA limit | |
| Lead 1993 to 2026 | 33 | 3% | 0 | 1.6 | 15 ug/L EPA limit | |
| Radium (226 + 228) 2008 to 2014 | 24 | 42% | 0 | 4.6 | 5 pCi/L EPA limit | |
| Uranium 2008 to 2026 | 22 | 5% | 0 | 1.93 | 30 ug/L EPA limit | |
| Chloride 1940 to 2026 | no limit | 158 | 100% | 29 | 760 | 250 mg/L nuisance level |
| Sodium 1940 to 2026 | no limit | 156 | 100% | 83 | 493 | 20 mg/L health guideline |
| Iron 1964 to 2026 | no limit | 74 | 64% | 40 | 73,000 | 300 ug/L nuisance level |
| Manganese 1971 to 2026 | no limit | 45 | 76% | 4 | 306 | 300 ug/L health guideline |
Sampled fewer than 10 times, too few to summarize: E. coli (3), Radon (3).
Over time
Share of samples above the limit by period. A cell needs ten samples to show; a comparison needs twenty in each period. Later periods sample fewer wells, and often the ones already known to have a problem.
| Contaminant | before 2000 | 2000s | 2010s | 2020s |
|---|---|---|---|---|
| Fluoride | 0%121 samples | 0%16 samples | n/a | n/a |
Closer than the county
See the sampled wells near your address
The same records, drawn around one point: which wells within a few miles were sampled and what they found, how deep the wells next to you were drilled, and any leaking tank or cleanup site within a mile.
Check my addressWhat this means
The contaminants most often above their limit here are gross alpha (8% of 13 samples) and nitrate (2% of 44 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 Robertson County
- 1Gross alpha8% of 13 local samples were above the limit.
- 2Nitrate2% of 44 local samples were above the limit.
- 3Coliform bacteriaRecommended for every private well, every year.
- 4RadonMedian local reading is 230 pCi/L.
- 5ChlorideDetected in 100% of local samples.
- 6FluorideDetected in 90% of local samples.
- 7ManganeseDetected in 76% of local samples.
- 8Volatile organic compounds (VOCs)27 leaking underground storage tank sites on record locally.
Test your Robertson County well for gross alpha, nitrate and coliform bacteria
Certified lab analysis of your own tap water, bottles and prepaid return shipping included. The Essential well panel covers arsenic, uranium, nitrate, lead, copper, manganese, iron, sodium and bacteria; radon and PFAS are add-ons.
Order the Tap Score well water test kit, from $209Already tested? Upload the report
Just want bacteria checked first? Tap Score coliform and E. coli test, $99. Coliform and E. coli are the tests every well needs every year.
Want a quick look before paying for a lab? Home well water test strips on Amazon check hardness, iron, pH and nitrate in minutes. They are a screen, not a result: arsenic, bacteria, uranium and PFAS need a certified lab.
Affiliate links: the merchant pays us a commission and the price is the same for you. It does not change what the data above says. As an Amazon Associate we earn from qualifying purchases.
Where to get a well tested in Texas: certified labs, state programs and prices.
Already have results back? Get your lab report read against the Robertson County numbers, $29. Every line explained, ranked by what matters, with the fix for each.
The rock under Robertson County
Texas coastal uplands aquifer system
Semiconsolidated sand. Coastal plain sands like these give steady yields at moderate depth. Salt water and sodium are the usual issues near the coast, and nitrate where the water table is shallow; arsenic and radon from bedrock are less common.
Classification from the USGS Principal Aquifers of the United States (national map, 2003 edition, GIS release 2015), read at the county centroid. A single well can sit in a different unit, especially near a boundary.
Official help in Texas
Two places to start that are not selling anything: the state program that answers private well questions, and its list of labs certified to run drinking water tests. A certified lab is the difference between a result you can act on and a number.
- Private Wells, Texas Groundwater Protection Committee
- Environmental Laboratory (NELAP) Accreditation, TCEQ
Contamination sources on record in Robertson County
TCEQ records 27 leaking underground storage tank sites in Robertson County, among 36 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.
- 27
- leaking underground storage tank sitesGasoline and heating oil that leaked from tanks move through groundwater as benzene, MTBE and other volatile organic compounds.
- 9
- lined landfills and transfer facilities
Treatment that fits the local profile
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
Manganese
Oxidizing filter (greensand, birm) whole-house; Water softener (low levels); Point-of-use reverse osmosis
Iron
Oxidizing filter whole-house; Water softener (low levels); Aeration plus filtration
Systems we would look at first
Some links below are affiliate links. If you buy through one, the merchant pays us a commission at no extra cost to you. It does not change which products we list or what the data says.
For gross alpha
Under-sink reverse osmosis system
under-sink or countertop, about $300
Look for NSF/ANSI 58 certification listing the contaminant you need removed.
For nitrate
Aquasana SmartFlow reverse osmosis
under-sink or countertop, about $225
Certified to NSF/ANSI 58 and 53 to reduce arsenic (96%, pentavalent), fluoride (90%), lead (99%), nitrate, nitrite and PFOA/PFOS at the kitchen tap, with a remineralizer.
For iron
Iron and manganese oxidizing filter
whole-house, at the point of entry, about $1,800
Air-injection or greensand media; fixes staining at the source.
Free, no obligation
Get on the list for a free in-home water test in Robertson County
No water treatment company serves Robertson County through Well Water Nerd yet. We are signing licensed companies on county by county: they test at your tap for free, walk you through the numbers, and quote treatment only if something needs fixing. Leave your details and you are first in line. Nothing is shared until a company joins for Robertson County, and you get an email naming it first.
Common questions
Is there arsenic in well water in Robertson County?
Arsenic was detected in 14% of 37 public well samples in Robertson 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 Robertson 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.
Counties near Robertson County
Closest first. Groundwater does not stop at a line on a map, so the next county over is a fair second opinion.
Want the numbers themselves? Download the Texas dataset as CSV, every county and town, with the sources named.
Sources
- Texas Water Development Board Groundwater Database: 735 samples in Robertson 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: 60 samples in Robertson 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.
- USGS national arsenic model (Ayotte 2017): estimated share of 1,382 people on private wells in Robertson County above 10 ug/L of arsenic, from geology, well depth and land use. County estimates of domestic well users with arsenic above 10 ug/L from the USGS national logistic regression model (Ayotte, Medalie and Qi, 2017), with private well population from the USGS 2015 county water-use compilation (Dieter and others, 2018). Retrieved September 15, 2026.
- TCEQ regulated sites: 36 regulated sites located in Robertson 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.