Arsenic and manganese are worth checking in Tarrant County wells.
2 worth checking, 4 rare out of 6 health checks.
From 39 wells tested in Tarrant County since 2000; your own well needs its own test. How to read this
*Arsenic and manganese: All of these tests come from the US Geological Survey, mostly before 2013 in one small part of the county, so this likely overstates them.
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 44 people 47,732 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 Tarrant County compares with Texas and the counties around it.
Each result puts Tarrant County next to the 6 counties that border it, on the chart's 0 to 50% scale.
These 2 are worth checking in Tarrant County.
Arsenic2 of 26 wells over
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.
Manganese2 of 27 wells over
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.
These 4 are rare in Tarrant County.
Nitrate0 of 35 wells over
Fluoride0 of 27 wells over
Uranium0 of 32 wells over
Lead0 of 27 wells over
Too few Tarrant County wells were tested for this one.
Radon in water1 well tested
None of the 1 Tarrant County wells tested for bacteria had it, but every well needs a yearly test.
Coliform bacteria0 of 1 wells had it
E. coli0 of 1 wells had it
E. coli means human or animal waste is getting in, so if a test of your Tarrant County well finds it, boil drinking water until the well is fixed.
Iron reached staining levels in 6 of 27 tested wells, and it isn't a health risk.
Iron stains6 of 27 wells had it
Most of the 39 wells tested in Tarrant County were last tested before 2010.
An old result shows the water as it was then, so treat these 39 wells as a starting point and test your own.
Most Tarrant 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 4 things to check in Tarrant County.
- Bacteria
- Nitrate
- Arsenic
- Manganese
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 340 feet.
That comes from 4,383 household wells in Texas's drilling records. Most wells of every kind here are 15 to 340 feet deep. Wells as deep as Tarrant 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 164 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 Tarrant County.
Tarrant 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 27 town water systems in Tarrant County test for PFAS. 11 of them had at least one test above 4 ng/L, the new EPA limit for PFOA and PFOS. The highest single result was 8.3 ng/L of PFOA. No well in Tarrant 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 Tarrant County
Is well water in Tarrant County safe to drink?
2 of 26 wells tested in Tarrant County had arsenic over the limit, about 1 in 13. Across Texas it's about 1 in 10. We don't rank this against other Texas counties, because most of these tests are old study samples. 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. So test your own well for arsenic before you count on it.
Can I get my well tested for free in Tarrant 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, arsenic and manganese, the tests that matter most in Tarrant County.
How deep are wells in Tarrant County?
Half the household wells here are shallower than 340 feet. Typical household wells here go deeper than in 164 of the 248 other Texas counties with enough drilling records.
How often should I test my well in Tarrant County?
None of the 1 wells tested for bacteria in Tarrant County had it, but the CDC still says to 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 Tarrant County numbers come from
- People on wells: 47,732 in Tarrant County, from EPA estimates built on the 2020 Census (Murray et al.).
- Lab tests: 244 well water samples from 39 wells in the Water Quality Portal, run by the USGS and EPA, 2000 to 2016.
- Well depths: 4,383 Texas drilling records for Tarrant County, gathered in the US Groundwater Well Database (Lin and others, 2024).
- Neighboring counties: the 6 counties that share a border with Tarrant County, from the Census Bureau's county adjacency file.
- Results marked likely overstated: our own check of who tested the wells, when and where.
- PFAS: EPA tests of 27 town water systems in Tarrant County under the Fifth Unregulated Contaminant Monitoring Rule, 2023 to 2025.
- Radon: Tarrant 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.