Nitrate is worth checking in York County wells.
1 worth checking, 2 rare out of 3 health checks.
From 19 wells tested in York County since 2000; your own well needs its own test. How to read this
Not charted, because fewer than 10 wells were tested: uranium (6), manganese (7), lead (7), fluoride (7).
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 116,313 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 York County compares with Pennsylvania and the counties around it.
Each result puts York County next to the 7 counties that border it, on the chart's 0 to 50% scale.
This one is worth checking in York County.
Nitrate2 of 17 wells over
* Likely overstated, so we don't rank it.
These 2 are rare in York County.
Radon in water0 of 11 wells over
Too few tested to show: Adams, Carroll, MD, Harford, MD.
Arsenic0 of 12 wells over
Too few tested to show: Adams, Baltimore, MD, Cumberland, Harford, MD.
Too few York County wells were tested for these 4.
Uranium6 wells tested
Manganese7 wells tested
Lead7 wells tested
Fluoride7 wells tested
Coliform bacteria turned up in 5 of 9 tested York County wells, so test for it every year.
Coliform bacteria5 of 9 wells had it
E. coli0 of 7 wells had it
E. coli means human or animal waste is getting in, so if a test of your York County well finds it, boil drinking water until the well is fixed.
Iron reached staining levels in 1 of 7 tested wells, and it isn't a health risk.
Iron stains7 wells tested
About 6 in 10 of the 19 wells tested in York County have a test from 2020 or later.
With 11 wells tested since 2020, age matters less here than who did the testing and why.
Most York 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 York County.
- Bacteria
- Nitrate
- 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 York County.
York 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 12 town water systems in York County test for PFAS. 6 of them had at least one test above 4 ng/L, the new EPA limit for PFOA and PFOS. The highest single result was 11 ng/L of PFOS. No well in York 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 York County
Is well water in York County safe to drink?
2 of 17 wells tested in York County had nitrate over the limit, about 1 in 8. Across Pennsylvania it's about 1 in 12. That's a bigger share than in 21 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 York 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 and arsenic, the tests that matter most in York County.
How does York County compare with the counties around it?
For nitrate, the share of tested wells over the limit: 3 of the 7 neighboring counties with data had a higher share than York County, at 12%. Lancaster had the most, at 50%. Groundwater doesn't stop at county lines, so Lancaster's 50% is worth knowing about if you live near it.
How often should I test my well in York County?
In York County, 5 of 9 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 York County numbers come from
- People on wells: 116,313 in York County, from EPA estimates built on the 2020 Census (Murray et al.).
- Lab tests: 93 well water samples from 19 wells in the Water Quality Portal, run by the USGS and EPA, 2000 to 2023.
- Neighboring counties: the 7 counties that share a border with York County, from the Census Bureau's county adjacency file.
- PFAS: EPA tests of 12 town water systems in York County under the Fifth Unregulated Contaminant Monitoring Rule, 2023 to 2025.
- Radon: York County is zone 1 on the EPA Map of Radon Zones.
- State programs and links: Department of Environmental Protection, checked November 1, 2026.