Nitrate, manganese and radon are worth checking in El Paso County wells.
3 worth checking, 4 rare out of 7 health checks.
From 107 wells tested in El Paso County since 2000; 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 12 people 59,907 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)
Likely here. Test your home's air first.
Radon zones: EPA map
Here's how El Paso County compares with Colorado and the counties around it.
Each result puts El Paso County next to the 6 counties that border it, on the chart's 0 to 50% scale.
These 3 are worth checking in El Paso County.
Nitrate11 of 105 wells over
Too few tested to show: Fremont, Lincoln, Teller.
Manganese7 of 86 wells over
Too few tested to show: Fremont, Lincoln, Teller.
Radon in water1 of 16 wells over
Too few tested to show: Fremont, Lincoln, Pueblo, Teller.
These 4 are rare in El Paso County.
Uranium0 of 68 wells over
Too few tested to show: Fremont, Lincoln, Teller.
Arsenic0 of 40 wells over
Too few tested to show: Fremont, Lincoln, Pueblo, Teller.
Lead0 of 40 wells over
Too few tested to show: Fremont, Lincoln, Pueblo, Teller.
Every well needs a bacteria test every year.
No bacteria tests from El Paso County wells are in the public data. Test every year anyway.
Iron reached staining levels in 11 of 86 tested wells, and it isn't a health risk.
Iron stains11 of 86 wells had it
Too few tested to show: Fremont, Lincoln, Teller.
About 5 in 10 of the 107 wells tested in El Paso County have a test from 2020 or later.
With 51 wells tested since 2020, age matters less here than who did the testing and why.
Most El Paso 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 5 things to check in El Paso County.
- Bacteria
- Nitrate
- Manganese
- Radon in water
- Arsenic
What Colorado offers well owners
- Free testingCDPHE offers free PFAS testing for private wells through its PFAS Testing and Assistance Program. See the program
- Certified labsColorado's list of certified labs
- Well recordsColorado's well record search
Half the household wells here are shallower than 320 feet.
That comes from 23,181 household wells in Colorado's drilling records. Most wells of every kind here are 192 to 430 feet deep. Wells as deep as El Paso 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 58 of the 63 other Colorado counties with enough drilling records.
Look up your own well's depth in Colorado'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 El Paso County.
El Paso County is in the EPA's highest radon zone. Radon from well water adds to the radon in your indoor air, so test your air first, and your water too if the air is high. Radon guide
Between 2023 and 2025 the EPA had 17 town water systems in El Paso County test for PFAS. 2 of them had at least one test above 4 ng/L, the new EPA limit for PFOA and PFOS. The highest single result was 16 ng/L of PFOS. Only 2 wells in El Paso 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 El Paso County
Is well water in El Paso County safe to drink?
11 of 105 wells tested in El Paso County had nitrate over the limit, about 1 in 10. Across Colorado it's about 1 in 10. That's a bigger share than in 11 of the 17 other Colorado counties with 10 or more tested wells, leaving out 4 counties whose results are likely overstated. So test your own well for nitrate before you count on it.
Can I get my well tested for free in El Paso County?
CDPHE offers free PFAS testing for private wells through its PFAS Testing and Assistance Program. If not, use a lab Colorado has certified for drinking water. Ask for bacteria, nitrate, manganese, radon in water and arsenic, the tests that matter most in El Paso County.
How deep are wells in El Paso County?
Half the household wells here are shallower than 320 feet. Typical household wells here go deeper than in 58 of the 63 other Colorado counties with enough drilling records.
How does El Paso County compare with the counties around it?
For nitrate, the share of tested wells over the limit: 1 of the 3 neighboring counties with data had a higher share than El Paso County, at 10%. Pueblo had the most, at 17%. Groundwater doesn't stop at county lines, so Pueblo's 17% is worth knowing about if you live near it.
How often should I test my well in El Paso County?
El Paso 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 El Paso County numbers come from
- People on wells: 59,907 in El Paso County, from EPA estimates built on the 2020 Census (Murray et al.).
- Lab tests: 1,409 well water samples from 107 wells in the Water Quality Portal, run by the USGS and EPA, 2000 to 2023.
- Well depths: 23,181 Colorado drilling records for El Paso County, gathered in the US Groundwater Well Database (Lin and others, 2024).
- Neighboring counties: the 6 counties that share a border with El Paso County, from the Census Bureau's county adjacency file.
- PFAS: EPA tests of 17 town water systems in El Paso County under the Fifth Unregulated Contaminant Monitoring Rule, 2023 to 2025.
- Radon: El Paso County is zone 1 on the EPA Map of Radon Zones.
- State programs and links: Department of Public Health and Environment, checked November 1, 2026.