Free testing, with limits
Texas A&M holds county well screenings around Texas, some free and some for a small fee. Check which tests it includes before you count on it for arsenic.
Texas's private well pageArsenic in Texas well water, by county
Arsenic is widespread, over the limit in 15% or more of tested wells, in 4 of the 18 Texas counties with 10 or more tested wells. A county's share tells you how likely a problem is nearby. Only a test of your own well tells you what's in it.
How Texas compares with the rest of the country
Across Texas, about 1 in 10 tested wells had arsenic over the EPA limit of 10 µg/L (95 of 997). Across all tested wells in the US it's about 1 in 9. Texas is about average, so the county you live in tells you more than the state does.
Why it matters: Drinking it for years raises the risk of skin, bladder and lung cancer.
Arsenic dissolves out of certain rocks and old sediments, so it can be high even where nobody has polluted anything.
Arsenic in tested wells, county by county
Share of each county's tested wells with at least one result over the EPA limit of 10 µg/L. Counties need 10 or more tested wells to be listed. Widespread means 15% or more, worth checking 5 to 15%, rare under 5%.
| County | Wells tested | Wells over the limit | Level |
|---|---|---|---|
| Terry County | 20 | Widespread | |
| Gaines County | 19 | Widespread | |
| Yoakum County | 22 | Widespread | |
| El Paso County | 54 | Widespread | |
| Tarrant County | 26 | Worth checking | |
| Montgomery County | 20 | Worth checking | |
| Pecos County | 31 | Rare | |
| Harris County | 162 | Rare | |
| Bexar County | 101 | Rare | |
| Hays County | 29 | Rare | |
| Travis County | 27 | Rare | |
| Medina County | 23 | Rare | |
| Comal County | 21 | Rare | |
| Uvalde County | 20 | Rare | |
| Williamson County | 19 | Rare | |
| Wilson County | 15 | Rare | |
| Atascosa County | 10 | Rare | |
| Lamb County | 10 | Rare |
* Likely overstated. These shares come from a narrow set of wells, so they probably run high for the county as a whole:
- Tarrant County: All of these tests come from the US Geological Survey, mostly before 2013 in one small part of the county, so this likely overstates it.
126 more Texas counties have 1 to 9 tested wells for arsenic, too few to rate.
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Where to get your well tested for arsenic in Texas
A lab Texas certifies
Ask for arsenic by name. Results from a certified lab count for a home sale or a loan.
Labs certified by TexasA mail-in kit
Fill the bottles at your kitchen tap and mail them back. We mark the kits that include arsenic.
Compare kitsKeep reading about wells in Texas
- Well water testing in Texas: how to get tested and what turns up statewide
- Arsenic in well water: where it comes from, what it does and how to remove it
- Nitrate in Texas wells, by county
- Uranium in Texas wells, by county
- Manganese in Texas wells, by county
- Lead in Texas wells, by county
Questions people ask about arsenic in Texas
Is there arsenic in Texas well water?
Arsenic is widespread, over the limit in 15% or more of tested wells, in 4 of the 18 Texas counties with 10 or more tested wells. Across Texas, about 1 in 10 tested wells had arsenic over the EPA limit of 10 µg/L (95 of 997). Across all tested wells in the US it's about 1 in 9. Texas is about average, so the county you live in tells you more than the state does.
Where can I get my well tested for arsenic in Texas?
Texas A&M holds county well screenings around Texas, some free and some for a small fee. If that doesn't cover you, use a lab certified by Texas for drinking water, or a mail-in kit that includes arsenic from a certified lab.
See Texas's list of certified labs, or compare mail-in kits.
Where these numbers come from
- Lab tests: Water Quality Portal (USGS and EPA), well samples since 2000. A well counts as over if any of its tests was over the EPA limit of 10 µg/L. Wells tested for studies and monitoring, not a random sample of homes.
- Likely overstated: our own check of who tested the wells, when and where. How we check.
- State programs and links: Texas Water Development Board and Texas Commission on Environmental Quality (TCEQ).