Manganese has turned up often in Franklin County wells, mostly from one small area.
1 likely overstated, 4 rare out of 5 health checks.
From 31 wells tested in Franklin County since 2002; your own well needs its own test. How to read this
*Manganese: Almost all of these tests come from the US Geological Survey in one small part of the county, so this likely overstates it.
Not charted, because fewer than 10 wells were tested: uranium (4), radon (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 3 people 52,615 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 Franklin County compares with Pennsylvania and the counties around it.
Each result puts Franklin County next to the 8 counties that border it, on the chart's 0 to 50% scale.
This one has turned up often here, mostly from one small area.
Manganese10 of 19 wells over
* Likely overstated, so we don't rank it.
Too few tested to show: Adams, Cumberland, Fulton, Huntingdon, Juniata, Perry.
Almost all of these tests come from the US Geological Survey in one small part of the county, so this likely overstates it.
These 4 are rare in Franklin County.
Nitrate1 of 24 wells over
Too few tested to show: Fulton, Huntingdon, Juniata, Perry.
Arsenic0 of 23 wells over
Too few tested to show: Adams, Cumberland, Fulton, Huntingdon, Juniata, Perry.
Fluoride0 of 17 wells over
Too few tested to show: Adams, Cumberland, Fulton, Huntingdon, Juniata, Perry.
Lead0 of 17 wells over
Too few tested to show: Adams, Cumberland, Fulton, Huntingdon, Juniata, Perry.
Too few Franklin County wells were tested for these 2.
Uranium4 wells tested
Radon in water7 wells tested
Coliform bacteria turned up in 2 of 5 tested Franklin County wells, so test for it every year.
Coliform bacteria2 of 5 wells had it
E. coli0 of 5 wells had it
E. coli means human or animal waste is getting in, so if a test of your Franklin County well finds it, boil drinking water until the well is fixed.
Iron reached staining levels in 10 of 22 tested wells, and it isn't a health risk.
Iron stains10 of 22 wells had it
Too few tested to show: Adams, Cumberland, Fulton, Huntingdon, Juniata, Perry.
About 6 in 10 of the 31 wells tested in Franklin County have a test from 2020 or later.
With 19 wells tested since 2020, age matters less here than who did the testing and why.
Most Franklin 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 Franklin County.
- Bacteria
- Nitrate
- Manganese
- 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 Franklin County.
Franklin 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 8 town water systems in Franklin County test for PFAS. 1 found some PFAS, all below the new limits. Only 9 wells in Franklin 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 Franklin County
Is well water in Franklin County safe to drink?
10 of 19 wells tested in Franklin County had manganese over the limit, about 5 in 10. Across Pennsylvania it's about 1 in 11. We don't rank this against other Pennsylvania counties, because most of these tests come from one small area. Almost all of these tests come from the US Geological Survey in one small part of the county, so this likely overstates it. So test your own well for manganese before you count on it.
Where can I get my well tested in Franklin 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, manganese and arsenic, the tests that matter most in Franklin County.
How does Franklin County compare with the counties around it?
For manganese, the share of tested wells over the limit: Franklin County, at 53%, had a higher share than all 2 neighboring counties with data. Groundwater doesn't stop at county lines, so Frederick, MD's 5% is worth knowing about if you live near it.
How often should I test my well in Franklin County?
In Franklin County, 2 of 5 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 Franklin County numbers come from
- People on wells: 52,615 in Franklin County, from EPA estimates built on the 2020 Census (Murray et al.).
- Lab tests: 849 well water samples from 31 wells in the Water Quality Portal, run by the USGS and EPA, 2002 to 2023.
- Neighboring counties: the 8 counties that share a border with Franklin County, from the Census Bureau's county adjacency file.
- Results marked likely overstated: our own check of who tested the wells, when and where.
- PFAS: EPA tests of 8 town water systems in Franklin County under the Fifth Unregulated Contaminant Monitoring Rule, 2023 to 2025.
- Radon: Franklin County is zone 1 on the EPA Map of Radon Zones.
- State programs and links: Department of Environmental Protection, checked November 1, 2026.