Health problems are rare in tested Travis County wells.
All 6 health checks came back rare here.
From 30 wells tested in Travis County since 2000; your own well needs its own test. How to read this
Not charted, because fewer than 10 wells were tested: radon (1).
Rare: under 5%Worth checking: 5 to 15%Widespread: 15%+
Lab results: Water Quality Portal (USGS and EPA)
Who drinks from a well here
About 1 in 35 people 36,422 people
Nobody else tests these wells. Only you do.
People on wells: EPA researchers' 2020 estimate
How deep wells go here
Deep wells: fewer surface germs, more minerals from the rock.
Well depths: US Groundwater Well Database
Radon risk (a gas from rock)
Less likely, but the EPA still says test your air.
Radon zones: EPA map
Here's how Travis County compares with Texas and the counties around it.
Each result puts Travis County next to the 6 counties that border it, on the chart's 0 to 50% scale.
All 6 health checks are rare in Travis County.
Arsenic0 of 27 wells over
Too few tested to show: Bastrop, Blanco, Burnet, Caldwell.
Nitrate0 of 30 wells over
Too few tested to show: Bastrop, Blanco, Caldwell.
Fluoride0 of 28 wells over
Too few tested to show: Bastrop, Blanco, Burnet, Caldwell.
Manganese0 of 28 wells over
Too few tested to show: Bastrop, Blanco, Burnet, Caldwell.
Uranium0 of 22 wells over
Too few tested to show: Bastrop, Blanco, Burnet, Caldwell.
Lead0 of 27 wells over
Too few tested to show: Bastrop, Blanco, Burnet, Caldwell.
Too few Travis County wells were tested for this one.
Radon in water1 well tested
Coliform bacteria turned up in 1 of 1 tested Travis County wells, so test for it every year.
Coliform bacteria1 of 1 wells had it
E. coli1 of 2 wells had it
E. coli means human or animal waste is getting in, so if a test of your Travis County well finds it, boil drinking water until the well is fixed.
Iron reached staining levels in 2 of 28 tested wells, and it isn't a health risk.
Iron stains2 of 28 wells had it
Too few tested to show: Bastrop, Blanco, Burnet, Caldwell.
Travis County has 30 tested wells, and the busiest decade for testing was the 2000s.
Only 4 of the 30 wells have a test from 2020 or later, so a fresh test of your own well tells you more than any of these.
Most Travis County wells in these records were tested for research or because someone suspected a problem, which can push the shares above what a typical home well would show (how we read the numbers).
One mail-in lab test covers the 3 things to check in Travis County.
- Bacteria
- Nitrate
- Arsenic
What Texas offers well owners
- Free testingTexas A&M AgriLife Extension's Texas Well Owner Network holds periodic county well water screenings, some free and some for a small per-sample fee. See the program
- Certified labsTexas's list of certified labs
- Well recordsTexas's well record search
Half the household wells here are shallower than 405 feet.
That comes from 3,350 household wells in Texas's drilling records. Most wells of every kind here are 15 to 470 feet deep. Wells as deep as Travis County's are usually better protected from fertilizer and bacteria at the surface, but they can pick up more of what's in the rock, like arsenic and uranium. Typical household wells here go deeper than in 205 of the 248 other Texas counties with enough drilling records.
Look up your own well's depth in Texas's well record search, or see how to find it.
Well depths: US Groundwater Well Database
Here's what we know about radon and PFAS in Travis County.
Travis County is in the EPA's lowest radon zone, so radon from well water is unlikely to be a problem. Radon guide
Between 2023 and 2025 the EPA had 20 town water systems in Travis County test for PFAS. 5 of them had at least one test above 4 ng/L, the new EPA limit for PFOA and PFOS. The highest single result was 14 ng/L of PFOS. No well in Travis County has public PFAS results, so the town systems are the best clue to what's in the groundwater nearby. PFAS guide
Radon zones: EPA Map of Radon Zones. PFAS: EPA tests of town water systems, 2023 to 2025
Questions people ask about well water in Travis County
Is well water in Travis County safe to drink?
Most tested wells in Travis County came in under the limits. Of 6 health checks with enough tests, nitrate came closest, at 0 of 30 wells over. Every well is different, so test yours for bacteria, nitrate and arsenic.
Can I get my well tested for free in Travis County?
Texas A&M AgriLife Extension's Texas Well Owner Network holds periodic county well water screenings, some free and some for a small per-sample fee. If not, use a lab Texas has certified for drinking water. Ask for bacteria, nitrate and arsenic, the tests that matter most in Travis County.
How deep are wells in Travis County?
Half the household wells here are shallower than 405 feet. Typical household wells here go deeper than in 205 of the 248 other Texas counties with enough drilling records.
How does Travis County compare with the counties around it?
For arsenic, the share of tested wells over the limit: Travis County and all 2 neighboring counties with data had no tested wells over the limit. Groundwater doesn't stop at county lines, so Hays's 0% is worth knowing about if you live near it.
How often should I test my well in Travis County?
In Travis County, 1 of 1 tested wells had coliform bacteria, so the CDC's advice matters here: test for bacteria and nitrate every year, and right away after a flood, a repair, or any change in taste or smell.
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Where the Travis County numbers come from
- People on wells: 36,422 in Travis County, from EPA estimates built on the 2020 Census (Murray et al.).
- Lab tests: 1,152 well water samples from 30 wells in the Water Quality Portal, run by the USGS and EPA, 2000 to 2022.
- Well depths: 3,350 Texas drilling records for Travis County, gathered in the US Groundwater Well Database (Lin and others, 2024).
- Neighboring counties: the 6 counties that share a border with Travis County, from the Census Bureau's county adjacency file.
- PFAS: EPA tests of 20 town water systems in Travis County under the Fifth Unregulated Contaminant Monitoring Rule, 2023 to 2025.
- Radon: Travis County is zone 3 on the EPA Map of Radon Zones.
- State programs and links: Texas Water Development Board and Texas Commission on Environmental Quality (TCEQ), checked November 1, 2026.