Well water in Hamilton County, Texas
In Hamilton County, 1% of 83 tested well samples exceeded the EPA limit for fluoride (4 mg/L), based on public data from Texas Water Development Board Groundwater Database.
The strongest signal is nitrate: 23% of 26 local samples were above the limit, too few samples to carry the headline but first on the test list below.
429 test results across 12 contaminants from at least 45 wells, 1960 to 2023; fluoride has the most at 83. 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 2,635 people in Hamilton County get their drinking water from a private well, per USGS 2015 county water use. That is about 32% of residents.
Separately, the USGS national arsenic model estimates that 2% of the 2,635 people on private wells in Hamilton County draw water above 10 ug/L (the model's range is 1% to 2%), from geology and well depth rather than local tests.
What individual samples found
Each row summarizes every public sample for that contaminant inside Hamilton 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 |
|---|---|---|---|---|---|---|
| Nitrate 1971 to 2023 | 26 | 65% | 0.081 | 19.9 | 10 mg/L EPA limit | |
| Fluoride 1960 to 2023 | 83 | 100% | 1 | 4.9 | 4 mg/L EPA limit | |
| Arsenic 1988 to 2023 | 26 | 4% | 0 | 1 | 10 ug/L EPA limit | |
| Copper 1988 to 2023 | 26 | 42% | 0 | 0.007 | 1.3 mg/L EPA limit | |
| Lead 1988 to 2023 | 26 | 19% | 0 | 3.55 | 15 ug/L EPA limit | |
| Sodium 1960 to 2023 | no limit | 83 | 100% | 140 | 408 | 20 mg/L health guideline |
| Chloride 1960 to 2023 | no limit | 83 | 100% | 40 | 209 | 250 mg/L nuisance level |
| Iron 1968 to 2023 | no limit | 29 | 48% | 0 | 714 | 300 ug/L nuisance level |
| Manganese 1988 to 2023 | no limit | 27 | 56% | 1.5 | 39 | 300 ug/L health guideline |
Sampled fewer than 10 times, too few to summarize: Gross alpha (7), Uranium (7), Radium (226 + 228) (6).
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 nitrate (23% of 26 samples) and fluoride (1% of 83 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 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 Hamilton County
- 1Nitrate23% of 26 local samples were above the limit.
- 2Fluoride1% of 83 local samples were above the limit.
- 3Coliform bacteriaRecommended for every private well, every year.
- 4ChlorideDetected in 100% of local samples.
- 5ManganeseDetected in 56% of local samples.
- 6Volatile organic compounds (VOCs)12 leaking underground storage tank sites on record locally.
Test your Hamilton County well for nitrate, fluoride 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 Hamilton County numbers, $29. Every line explained, ranked by what matters, with the fix for each.
The rock under Hamilton County
Edwards-Trinity aquifer system
Sandstone and carbonate-rock. Layered sandstone and limestone means a well may draw from either. Hardness and iron are routine, and the limestone layers can carry bacteria and nitrate from the surface quickly, so test for both yearly.
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 Hamilton County
TCEQ records 12 leaking underground storage tank sites in Hamilton County, among 16 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.
- 12
- leaking underground storage tank sitesGasoline and heating oil that leaked from tanks move through groundwater as benzene, MTBE and other volatile organic compounds.
- 4
- lined landfills and transfer facilities
Treatment that fits the local profile
Nitrate
Point-of-use reverse osmosis; Anion exchange; Distillation
Fluoride
Point-of-use reverse osmosis; Activated alumina; Distillation
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 nitrate
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 Hamilton County
No water treatment company serves Hamilton 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 Hamilton County, and you get an email naming it first.
Common questions
Is there arsenic in well water in Hamilton County?
Arsenic was detected in 4% of 26 public well samples in Hamilton 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 Hamilton 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 Hamilton 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: 429 samples in Hamilton 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 national arsenic model (Ayotte 2017): estimated share of 2,635 people on private wells in Hamilton 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: 16 regulated sites located in Hamilton 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.