Manganese is worth checking in Oswego County wells.
1 worth checking, 6 rare out of 7 health checks.
From 22 wells tested in Oswego County since 2007; 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 2 people 47,680 people
Nobody else tests these wells. Only you do.
People on wells: EPA researchers' 2020 estimate
How deep wells go here
Middle depth: some shelter from the surface, not complete.
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 Oswego County compares with New York and the counties around it.
Each result puts Oswego County next to the 6 counties that border it, on the chart's 0 to 50% scale.
This one is worth checking in Oswego County.
Manganese2 of 22 wells over
These 6 are rare in Oswego County.
Arsenic1 of 22 wells over
Nitrate0 of 22 wells over
Lead0 of 22 wells over
Radon in water0 of 15 wells over
Uranium0 of 22 wells over
Coliform bacteria turned up in 3 of 15 tested Oswego County wells, so test for it every year.
Coliform bacteria3 of 15 wells had it
E. coli0 of 14 wells had it
E. coli means human or animal waste is getting in, so if a test of your Oswego County well finds it, boil drinking water until the well is fixed.
Iron reached staining levels in 6 of 22 tested wells, and it isn't a health risk.
Iron stains6 of 22 wells had it
Oswego County has 22 tested wells, and the busiest decade for testing was the 2010s.
Only 1 of the 22 wells have a test from 2020 or later, so a fresh test of your own well tells you more than any of these.
Most Oswego 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 Oswego County.
- Bacteria
- Nitrate
- Manganese
- Arsenic
What New York offers well owners
- Free testingThe Private Well PFAS Testing and Mitigation Rebate Pilot Program offers limited free PFAS testing and treatment rebates in Dutchess, Orange, Putnam, Suffolk, Ulster and Westchester counties. See the program
- Certified labsNew York's list of certified labs
- Well recordsNew York's well record search
Half the household wells here are shallower than 74 feet.
That comes from 1,899 household wells in New York's drilling records. Most wells of every kind here are 50 to 102 feet deep. Wells as deep as Oswego 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 are shallower than in 50 of the 56 other New York counties with enough drilling records.
Look up your own well's depth in New York'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 Oswego County.
Oswego 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 4 town water systems in Oswego County test for PFAS. None found any. No well in Oswego 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 Oswego County
Is well water in Oswego County safe to drink?
2 of 22 wells tested in Oswego County had manganese over the limit, about 1 in 11. Across New York it's about 1 in 7. That's a bigger share than in 28 of the 50 other New York counties with 10 or more tested wells, leaving out 1 county whose results are likely overstated. So test your own well for manganese before you count on it.
Can I get my well tested for free in Oswego County?
The Private Well PFAS Testing and Mitigation Rebate Pilot Program offers limited free PFAS testing and treatment rebates in Dutchess, Orange, Putnam, Suffolk, Ulster and Westchester counties. If not, use a lab New York has certified for drinking water. Ask for bacteria, nitrate, manganese and arsenic, the tests that matter most in Oswego County.
How deep are wells in Oswego County?
Half the household wells here are shallower than 74 feet. Typical household wells here are shallower than in 50 of the 56 other New York counties with enough drilling records.
How does Oswego County compare with the counties around it?
For manganese, the share of tested wells over the limit: 1 of the 6 neighboring counties with data had a higher share than Oswego County, at 9%. Onondaga had the most, at 16%. Groundwater doesn't stop at county lines, so Onondaga's 16% is worth knowing about if you live near it.
How often should I test my well in Oswego County?
In Oswego County, 3 of 15 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 Oswego County numbers come from
- People on wells: 47,680 in Oswego County, from EPA estimates built on the 2020 Census (Murray et al.).
- Lab tests: 255 well water samples from 22 wells in the Water Quality Portal, run by the USGS and EPA, 2007 to 2022.
- Well depths: 1,899 New York drilling records for Oswego County, gathered in the US Groundwater Well Database (Lin and others, 2024).
- Neighboring counties: the 6 counties that share a border with Oswego County, from the Census Bureau's county adjacency file.
- PFAS: EPA tests of 4 town water systems in Oswego County under the Fifth Unregulated Contaminant Monitoring Rule, 2023 to 2025.
- Radon: Oswego County is zone 2 on the EPA Map of Radon Zones.
- State programs and links: Department of Health, checked November 1, 2026.