Health problems are rare in tested McKinley County wells.
All 6 health checks came back rare here.
From 64 wells tested in McKinley County since 2009; your own well needs its own test. How to read this
Not charted, because fewer than 10 wells were tested: radon (3).
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 28,212 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)
Possible here. A home air test is inexpensive.
Radon zones: EPA map
Here's how McKinley County compares with New Mexico and the counties around it.
Each result puts McKinley County next to the 4 counties that border it, on the chart's 0 to 50% scale.
All 6 health checks are rare in McKinley County.
Fluoride1 of 62 wells over
Manganese0 of 13 wells over
Arsenic0 of 13 wells over
Uranium0 of 13 wells over
* Likely overstated, so we don't rank it.
Too few tested to show: Apache, AZ.
Nitrate0 of 13 wells over
* Likely overstated, so we don't rank it.
Lead0 of 13 wells over
Too few McKinley County wells were tested for this one.
Radon in water3 wells tested
None of the 2 McKinley County wells tested for bacteria had it, but every well needs a yearly test.
Coliform bacteria0 of 2 wells had it
E. coli0 of 2 wells had it
E. coli means human or animal waste is getting in, so if a test of your McKinley County well finds it, boil drinking water until the well is fixed.
Iron reached staining levels in 2 of 13 tested wells, and it isn't a health risk.
Iron stains2 of 13 wells had it
Most of the 64 wells tested in McKinley County were last tested before 2010.
An old result shows the water as it was then, so treat these 64 wells as a starting point and test your own.
Most McKinley 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 McKinley County.
- Bacteria
- Nitrate
- Arsenic
What New Mexico offers well owners
- Free testingNMED offers free well water screening at water fairs and limited free nitrate, iron and fluoride screening at some field offices; these do not replace certified lab tests. See the program
- Certified labsNew Mexico's list of certified labs
- Well recordsNew Mexico's well record search
Half the household wells here are shallower than 400 feet.
That comes from 737 household wells in New Mexico's drilling records. Most wells of every kind here are 240 to 700 feet deep. Wells as deep as McKinley 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. That's the deepest typical depth for household wells among the 32 New Mexico counties with enough drilling records.
Look up your own well's depth in New Mexico'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 McKinley County.
McKinley County is in the EPA's middle radon zone. An indoor air test is cheap and tells you whether to look at your water. Radon guide
Between 2023 and 2025 the EPA had 1 town water system in McKinley County test for PFAS. None found any. Only 2 wells in McKinley County have 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 McKinley County
Is well water in McKinley County safe to drink?
Most tested wells in McKinley County came in under the limits. Of 6 health checks with enough tests, fluoride came closest, at 1 of 62 wells over. Every well is different, so test yours for bacteria, nitrate and arsenic.
Can I get my well tested for free in McKinley County?
NMED offers free well water screening at water fairs and limited free nitrate, iron and fluoride screening at some field offices; these do not replace certified lab tests. If not, use a lab New Mexico has certified for drinking water. Ask for bacteria, nitrate and arsenic, the tests that matter most in McKinley County.
How deep are wells in McKinley County?
Half the household wells here are shallower than 400 feet. That's the deepest typical depth for household wells among the 32 New Mexico counties with enough drilling records.
How does McKinley County compare with the counties around it?
For fluoride, the share of tested wells over the limit: 2 of the 4 neighboring counties with data had a higher share than McKinley County, at 2%. San Juan had the most, at 10%. Groundwater doesn't stop at county lines, so San Juan's 10% is worth knowing about if you live near it.
How often should I test my well in McKinley County?
None of the 2 wells tested for bacteria in McKinley 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 McKinley County numbers come from
- People on wells: 28,212 in McKinley County, from EPA estimates built on the 2020 Census (Murray et al.).
- Lab tests: 147 well water samples from 64 wells in the Water Quality Portal, run by the USGS and EPA, 2009 to 2021.
- Well depths: 737 New Mexico drilling records for McKinley County, gathered in the US Groundwater Well Database (Lin and others, 2024).
- Neighboring counties: the 4 counties that share a border with McKinley County, from the Census Bureau's county adjacency file.
- PFAS: EPA tests of 1 town water systems in McKinley County under the Fifth Unregulated Contaminant Monitoring Rule, 2023 to 2025.
- Radon: McKinley County is zone 2 on the EPA Map of Radon Zones.
- State programs and links: Environment Department, checked November 1, 2026.