Nitrate is widespread in Cumberland County wells.
1 widespread, 1 worth checking out of 2 health checks.
From 43 wells tested in Cumberland County since 2000; your own well needs its own test. How to read this
Not charted, because fewer than 10 wells were tested: arsenic (8), uranium (1), manganese (1), lead (1), fluoride (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
1 in 4 people 58,209 people
Nobody else tests these wells. Only you do.
People on wells: EPA researchers' 2020 estimate
Radon risk (a gas from rock)
Likely here. Test your home's air first.
Radon zones: EPA map
Here's how Cumberland County compares with Pennsylvania and the counties around it.
Each result puts Cumberland County next to the 5 counties that border it, on the chart's 0 to 50% scale.
This one is widespread in Cumberland County wells.
Nitrate3 of 20 wells over
Too few tested to show: Perry.
This one is worth checking in Cumberland County.
Radon in water1 of 18 wells over
Too few tested to show: Adams, Franklin, Perry.
Too few Cumberland County wells were tested for these 5.
Arsenic8 wells tested
Uranium1 well tested
Manganese1 well tested
Lead1 well tested
Fluoride1 well tested
Coliform bacteria turned up in 27 of 33 tested Cumberland County wells, so test for it every year.
Coliform bacteria27 of 33 wells had it
Too few tested to show: Franklin, Perry, York.
E. coli8 of 29 wells had it
Too few tested to show: Dauphin, Franklin, Perry, York.
E. coli means human or animal waste is getting in, so if a test of your Cumberland County well finds it, boil drinking water until the well is fixed.
Iron reached staining levels in 2 of 3 tested wells, and it isn't a health risk.
Iron stains3 wells tested
Most of the 43 wells tested in Cumberland County were last tested before 2010.
An old result shows the water as it was then, so treat these 43 wells as a starting point and test your own.
Most Cumberland 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 Cumberland County.
- Bacteria
- Nitrate
- Radon in water
- Arsenic
What Pennsylvania offers well owners
- Free testingWe didn't find a free program for all of Pennsylvania. Pennsylvania's private well page
- Certified labsPennsylvania's list of certified labs
- Well recordsPennsylvania's well record search
Here's what we know about radon and PFAS in Cumberland County.
Cumberland 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 9 town water systems in Cumberland 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 17 ng/L of PFOS. No well in Cumberland 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 Cumberland County
Is well water in Cumberland County safe to drink?
3 of 20 wells tested in Cumberland County had nitrate over the limit, about 1 in 10. Across Pennsylvania it's about 1 in 12. That's a bigger share than in 23 of the 26 other Pennsylvania counties with 10 or more tested wells, leaving out 1 county whose results are likely overstated. So test your own well for nitrate before you count on it.
Where can I get my well tested in Cumberland County?
Use a lab Pennsylvania has certified for drinking water. Pennsylvania's list is linked above, in the box about testing. Ask for bacteria, nitrate, radon in water and arsenic, the tests that matter most in Cumberland County.
How does Cumberland County compare with the counties around it?
For nitrate, the share of tested wells over the limit: Cumberland County, at 15%, had a higher share than all 4 neighboring counties with data. Groundwater doesn't stop at county lines, so York's 12% is worth knowing about if you live near it.
How often should I test my well in Cumberland County?
In Cumberland County, 27 of 33 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 Cumberland County numbers come from
- People on wells: 58,209 in Cumberland County, from EPA estimates built on the 2020 Census (Murray et al.).
- Lab tests: 236 well water samples from 43 wells in the Water Quality Portal, run by the USGS and EPA, 2000 to 2023.
- Neighboring counties: the 5 counties that share a border with Cumberland County, from the Census Bureau's county adjacency file.
- PFAS: EPA tests of 9 town water systems in Cumberland County under the Fifth Unregulated Contaminant Monitoring Rule, 2023 to 2025.
- Radon: Cumberland County is zone 1 on the EPA Map of Radon Zones.
- State programs and links: Department of Environmental Protection, checked November 1, 2026.