Health problems are rare in tested Nassau County wells.
All 5 health checks came back rare here.
From 34 wells tested in Nassau County since 2000; your own well needs its own test. How to read this
Not charted, because fewer than 10 wells were tested: uranium (3), radon (2).
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 37,738 people
Nobody else tests these wells. Only you do.
People on wells: EPA researchers' 2020 estimate
Radon risk (a gas from rock)
Less likely, but the EPA still says test your air.
Radon zones: EPA map
Here's how Nassau County compares with Florida and the counties around it.
Each result puts Nassau County next to the 4 counties that border it, on the chart's 0 to 50% scale.
All 5 health checks are rare in Nassau County.
Arsenic1 of 32 wells over
Too few tested to show: Charlton, GA.
Lead1 of 33 wells over
Too few tested to show: Charlton, GA.
Nitrate0 of 28 wells over
Too few tested to show: Charlton, GA.
Fluoride0 of 16 wells over
Too few tested to show: Charlton, GA.
Manganese0 of 33 wells over
Too few tested to show: Charlton, GA.
Too few Nassau County wells were tested for these 2.
Uranium3 wells tested
Radon in water2 wells tested
Coliform bacteria turned up in 4 of 15 tested Nassau County wells, so test for it every year.
Coliform bacteria4 of 15 wells had it
Too few tested to show: Camden, GA, Charlton, GA.
Most of Florida's bacteria results come from shallow monitoring-network wells, so they aren't a guide to household wells.
E. coli1 of 10 wells had it
E. coli means human or animal waste is getting in, so if a test of your Nassau County well finds it, boil drinking water until the well is fixed.
Iron reached staining levels in 7 of 33 tested wells, and it isn't a health risk.
Iron stains7 of 33 wells had it
Too few tested to show: Charlton, GA.
About 8 in 10 of the 34 wells tested in Nassau County have a test from 2020 or later.
With 26 wells tested since 2020, age matters less here than who did the testing and why.
Most Nassau 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 Nassau County.
- Bacteria
- Nitrate
- Arsenic
What Florida offers well owners
- Free testingSome county health departments may test for certain toxic substances free of charge. See the program
- Certified labsFlorida's list of certified labs
- Well recordsWe didn't find an online search.
- New wellsNo statewide rule. We didn't find a local rule for Nassau County, so ask its health department.
Here's what we know about radon and PFAS in Nassau County.
Nassau County is in the EPA's lowest radon zone, so radon from well water is unlikely to be a problem. Radon guide
Between 2023 and 2025 the EPA had 3 town water systems in Nassau County test for PFAS. None found any. No well in Nassau 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 Nassau County
Is well water in Nassau County safe to drink?
Most tested wells in Nassau County came in under the limits. Of 5 health checks with enough tests, arsenic came closest, at 1 of 32 wells over. Every well is different, so test yours for bacteria, nitrate and arsenic.
Can I get my well tested for free in Nassau County?
Some county health departments may test for certain toxic substances free of charge. If not, use a lab Florida has certified for drinking water. Ask for bacteria, nitrate and arsenic, the tests that matter most in Nassau County.
How does Nassau County compare with the counties around it?
For arsenic, the share of tested wells over the limit: 2 of the 3 neighboring counties with data had a higher share than Nassau County, at 3%. Camden, GA had the most, at 18%. Groundwater doesn't stop at county lines, so Camden, GA's 18% is worth knowing about if you live near it.
How often should I test my well in Nassau County?
In Nassau County, 4 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 Nassau County numbers come from
- People on wells: 37,738 in Nassau County, from EPA estimates built on the 2020 Census (Murray et al.).
- Lab tests: 594 well water samples from 34 wells in the Water Quality Portal, run by the USGS and EPA, 2000 to 2025.
- Neighboring counties: the 4 counties that share a border with Nassau County, from the Census Bureau's county adjacency file.
- PFAS: EPA tests of 3 town water systems in Nassau County under the Fifth Unregulated Contaminant Monitoring Rule, 2023 to 2025.
- Radon: Nassau County is zone 3 on the EPA Map of Radon Zones.
- State programs and links: Department of Health, checked November 1, 2026.