Health problems are rare in tested Seminole County wells.
All 5 health checks came back rare here.
From 67 wells tested in Seminole County since 2000; 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 9 people 50,368 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 Seminole County compares with Florida and the counties around it.
Each result puts Seminole County next to the 4 counties that border it, on the chart's 0 to 50% scale.
All 5 health checks are rare in Seminole County.
Arsenic1 of 58 wells over
Lead1 of 63 wells over
Nitrate0 of 61 wells over
Fluoride0 of 18 wells over
Manganese0 of 63 wells over
Coliform bacteria turned up in 6 of 17 tested Seminole County wells, so test for it every year.
Coliform bacteria6 of 17 wells had it
Most of Florida's bacteria results come from shallow monitoring-network wells, so they aren't a guide to household wells.
E. coli3 of 11 wells had it
E. coli means human or animal waste is getting in, so if a test of your Seminole County well finds it, boil drinking water until the well is fixed.
Iron reached staining levels in 31 of 67 tested wells, and it isn't a health risk.
Iron stains31 of 67 wells had it
About 9 in 10 of the 67 wells tested in Seminole County have a test from 2020 or later.
With 58 wells tested since 2020, age matters less here than who did the testing and why.
Most Seminole 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 Seminole 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 Seminole County, so ask its health department.
Here's what we know about radon and PFAS in Seminole County.
Seminole 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 15 town water systems in Seminole County test for PFAS. 3 of them had at least one test above 4 ng/L, the new EPA limit for PFOA and PFOS. The highest single result was 6.9 ng/L of PFOS. No well in Seminole 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 Seminole County
Is well water in Seminole County safe to drink?
Most tested wells in Seminole County came in under the limits. Of 5 health checks with enough tests, arsenic came closest, at 1 of 58 wells over. Every well is different, so test yours for bacteria, nitrate and arsenic.
Can I get my well tested for free in Seminole 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 Seminole County.
How does Seminole County compare with the counties around it?
For arsenic, the share of tested wells over the limit: 2 of the 4 neighboring counties with data had a higher share than Seminole County, at 2%. Brevard had the most, at 6%. Groundwater doesn't stop at county lines, so Brevard's 6% is worth knowing about if you live near it.
How often should I test my well in Seminole County?
In Seminole County, 6 of 17 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 Seminole County numbers come from
- People on wells: 50,368 in Seminole County, from EPA estimates built on the 2020 Census (Murray et al.).
- Lab tests: 1,549 well water samples from 67 wells in the Water Quality Portal, run by the USGS and EPA, 2000 to 2026.
- Neighboring counties: the 4 counties that share a border with Seminole County, from the Census Bureau's county adjacency file.
- PFAS: EPA tests of 15 town water systems in Seminole County under the Fifth Unregulated Contaminant Monitoring Rule, 2023 to 2025.
- Radon: Seminole County is zone 3 on the EPA Map of Radon Zones.
- State programs and links: Department of Health, checked November 1, 2026.