Nitrate is widespread in Garfield County wells.
1 widespread, 2 rare out of 3 health checks.
From 26 wells tested in Garfield County since 2001; your own well needs its own test. How to read this
Rare: under 5%Worth checking: 5 to 15%Widespread: 15%+
Lab results: Water Quality Portal (USGS and EPA)
Who drinks from a well here
1 in 3 people 22,729 people
Nobody else tests these wells. Only you do.
People on wells: EPA researchers' 2020 estimate
How deep wells go here
Shallow wells: watch for fertilizer and germs from above.
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 Garfield County compares with Oklahoma and the counties around it.
Each result puts Garfield County next to the 7 counties that border it, on the chart's 0 to 50% scale.
This one is widespread in Garfield County wells.
Nitrate8 of 26 wells over
Too few tested to show: Grant, Noble.
These 2 are rare in Garfield County.
Manganese0 of 16 wells over
Too few tested to show: Grant, Noble.
Fluoride0 of 16 wells over
Too few tested to show: Grant, Noble.
Every well needs a bacteria test every year.
No bacteria tests from Garfield County wells are in the public data. Test every year anyway.
Iron reached staining levels in 0 of 16 tested wells, and it isn't a health risk.
Iron stains0 of 16 wells had it
Too few tested to show: Grant, Noble.
Most of the 26 wells tested in Garfield County were last tested before 2010.
An old result shows the water as it was then, so treat these 26 wells as a starting point and test your own.
Most Garfield 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 Garfield County.
- Bacteria
- Nitrate
- Arsenic
What Oklahoma offers well owners
- Free testingWe didn't find a free program for all of Oklahoma. Oklahoma's private well page
- Certified labsOklahoma's list of certified labs
- Well recordsOklahoma's well record search
Half the household wells here are shallower than 47 feet.
That comes from 3,196 household wells in Oklahoma's drilling records. Most wells of every kind here are 25 to 51 feet deep. Wells as shallow as Garfield County's pick up bacteria and nitrate from the surface more easily, so the yearly test matters even more here. Typical household wells here are shallower than in 71 of the 75 other Oklahoma counties with enough drilling records.
Look up your own well's depth in Oklahoma'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 Garfield County.
Garfield 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 1 town water system in Garfield County test for PFAS. None found any. No well in Garfield 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 Garfield County
Is well water in Garfield County safe to drink?
8 of 26 wells tested in Garfield County had nitrate over the limit, about 3 in 10. Across Oklahoma it's about 1 in 8. That's a bigger share than in 38 of the 39 other Oklahoma counties with 10 or more tested wells. So test your own well for nitrate before you count on it.
Where can I get my well tested in Garfield County?
Use a lab Oklahoma has certified for drinking water. Oklahoma's list is linked above, in the box about testing. Ask for bacteria, nitrate and arsenic, the tests that matter most in Garfield County.
How deep are wells in Garfield County?
Half the household wells here are shallower than 47 feet. Typical household wells here are shallower than in 71 of the 75 other Oklahoma counties with enough drilling records.
How does Garfield County compare with the counties around it?
For nitrate, the share of tested wells over the limit: Garfield County, at 31%, had a higher share than all 5 neighboring counties with data. Groundwater doesn't stop at county lines, so Kingfisher's 30% is worth knowing about if you live near it.
How often should I test my well in Garfield County?
Garfield County has no public bacteria results for wells, so follow the CDC's advice: 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 Garfield County numbers come from
- People on wells: 22,729 in Garfield County, from EPA estimates built on the 2020 Census (Murray et al.).
- Lab tests: 143 well water samples from 26 wells in the Water Quality Portal, run by the USGS and EPA, 2001 to 2013.
- Well depths: 3,196 Oklahoma drilling records for Garfield County, gathered in the US Groundwater Well Database (Lin and others, 2024).
- Neighboring counties: the 7 counties that share a border with Garfield County, from the Census Bureau's county adjacency file.
- PFAS: EPA tests of 1 town water systems in Garfield County under the Fifth Unregulated Contaminant Monitoring Rule, 2023 to 2025.
- Radon: Garfield County is zone 3 on the EPA Map of Radon Zones.
- State programs and links: Department of Environmental Quality, checked November 1, 2026.