Well water in Jefferson County, Florida
In Jefferson County, none of 106 tested well samples exceeded the EPA limit for fluoride, based on public data from USGS Water Quality Portal.
The strongest signal is coliform bacteria: Recommended for every private well, every year, too few samples to carry the headline but first on the test list below.
446 test results across 11 contaminants from at least 32 wells, 1982 to 2025; fluoride has the most at 106. Data refreshed September 15, 2026.
Compiled by Nick at Well Water Nerd from public records. How these pages are built
An estimated 8,811 people in Jefferson County get their drinking water from a private well, per USGS 2015 county water use. That is about 63% of residents.
Separately, the USGS national arsenic model estimates that 2% of the 8,811 people on private wells in Jefferson County draw water above 10 ug/L (the model's range is 2% to 4%), from geology and well depth rather than local tests.
What individual samples found
Each row summarizes every public sample for that contaminant inside Jefferson County. Above limit means above the EPA maximum contaminant level; where EPA has no enforceable limit, the row shows a health guideline or nuisance level instead.
| Contaminant | Above limit | Samples | Detected | Median | Highest | Limit |
|---|---|---|---|---|---|---|
| Fluoride 1982 to 2025 | 106 | 100% | 0.16 | 0.73 | 4 mg/L EPA limit | |
| Copper 2002 to 2025 | 56 | 100% | 0.001 | 0.018 | 1.3 mg/L EPA limit | |
| Lead 2002 to 2025 | 56 | 100% | 0.109 | 5.79 | 15 ug/L EPA limit | |
| Arsenic 2002 to 2025 | 56 | 100% | 0.5 | 2.69 | 10 ug/L EPA limit | |
| Nitrate 1999 to 2025 | 51 | 98% | 0.21 | 3.69 | 10 mg/L EPA limit | |
| Iron 1982 to 2025 | no limit | 57 | 96% | 190 | 2,420 | 300 ug/L nuisance level |
| Manganese 1982 to 2025 | no limit | 57 | 100% | 19.1 | 57.9 | 300 ug/L health guideline |
Sampled fewer than 10 times, too few to summarize: Radium (226 + 228) (2), Uranium (1), Sodium (3), Radon (1).
Over time
Share of samples above the limit by period. A cell needs ten samples to show; a comparison needs twenty in each period. Later periods sample fewer wells, and often the ones already known to have a problem.
| Contaminant | before 2000 | 2000s | 2010s | 2020s |
|---|---|---|---|---|
| Fluoride | n/a | n/a | 0%15 samples | 0%88 samples |
| Copper | n/a | n/a | 0%15 samples | 0%40 samples |
| Lead | n/a | n/a | 0%15 samples | 0%40 samples |
| Arsenic | n/a | n/a | 0%15 samples | 0%40 samples |
Closer than the county
See the sampled wells near your address
The same records, drawn around one point: which wells within a few miles were sampled and what they found, how deep the wells next to you were drilled, and any leaking tank or cleanup site within a mile.
Check my addressWhat this means
Among contaminants with a federal limit, no tested sample in Jefferson County came back above it. That is reassuring, but sampling is uneven: wells that were never tested are not in this data.
Iron and Manganese are widespread in local groundwater. They are mainly a staining and taste problem, but high manganese also carries a health advisory for infants.
What to test for in Jefferson County
- 1Coliform bacteriaRecommended for every private well, every year.
- 2RadonMedian local reading is 360 pCi/L.
- 3NitrateRecommended for every private well, especially near farms or septic systems.
- 4FluorideDetected in 100% of local samples.
- 5CopperDetected in 100% of local samples.
- 6ManganeseDetected in 100% of local samples.
- 7IronDetected in 96% of local samples.
- 8Volatile organic compounds (VOCs)117 leaking underground storage tank sites on record locally.
Test your Jefferson County well for coliform bacteria, radon and nitrate
Certified lab analysis of your own tap water, bottles and prepaid return shipping included. The Essential well panel covers arsenic, uranium, nitrate, lead, copper, manganese, iron, sodium and bacteria; radon and PFAS are add-ons.
Order the Tap Score well water test kit, from $209Already tested? Upload the report
Just want bacteria checked first? Tap Score coliform and E. coli test, $99. Coliform and E. coli are the tests every well needs every year.
Want a quick look before paying for a lab? Home well water test strips on Amazon check hardness, iron, pH and nitrate in minutes. They are a screen, not a result: arsenic, bacteria, uranium and PFAS need a certified lab.
Affiliate links: the merchant pays us a commission and the price is the same for you. It does not change what the data above says. As an Amazon Associate we earn from qualifying purchases.
Where to get a well tested in Florida: certified labs, state programs and prices.
Already have results back? Get your lab report read against the Jefferson County numbers, $29. Every line explained, ranked by what matters, with the fix for each.
The rock under Jefferson County
Not a principal aquifer
The USGS map places this area outside any principal aquifer, which usually means wells here draw from fractured bedrock or thin local deposits rather than a large regional aquifer. Bedrock wells of that kind are where arsenic, radon and uranium turn up, and yields vary from well to well.
Classification from the USGS Principal Aquifers of the United States (national map, 2003 edition, GIS release 2015), read at the county centroid. A single well can sit in a different unit, especially near a boundary.
Official help in Florida
Two places to start that are not selling anything: the state program that answers private well questions, and its list of labs certified to run drinking water tests. A certified lab is the difference between a result you can act on and a number.
- Private Well Water Testing, Florida Department of Health
- NELAP Certified Laboratory Search, Florida DEP
Contamination sources on record in Jefferson County
FDEP records 117 leaking underground storage tank sites in Jefferson County, among 149 regulated sites in total. Groundwater does not follow property lines, so a well within a few hundred feet of one of these is worth testing for what that site could release.
- 117
- leaking underground storage tank sitesGasoline and heating oil that leaked from tanks move through groundwater as benzene, MTBE and other volatile organic compounds.
- 32
- other remediation projects
Treatment that fits the local profile
Iron
Oxidizing filter whole-house; Water softener (low levels); Aeration plus filtration
Systems we would look at first
Some links below are affiliate links. If you buy through one, the merchant pays us a commission at no extra cost to you. It does not change which products we list or what the data says.
For iron
Iron and manganese oxidizing filter
whole-house, at the point of entry, about $1,800
Air-injection or greensand media; fixes staining at the source.
Free, no obligation
Get on the list for a free in-home water test in Jefferson County
No water treatment company serves Jefferson County through Well Water Nerd yet. We are signing licensed companies on county by county: they test at your tap for free, walk you through the numbers, and quote treatment only if something needs fixing. Leave your details and you are first in line. Nothing is shared until a company joins for Jefferson County, and you get an email naming it first.
Common questions
Is there arsenic in well water in Jefferson County?
Arsenic was detected in 100% of 56 public well samples in Jefferson County, and 0% were above the EPA limit of 10 ug/L. Arsenic has no taste or smell; a lab test is the only way to know your level.
How often should I test a private well in Jefferson County?
Test for bacteria and nitrate every year. Test once for arsenic, uranium, radon, fluoride, manganese and PFAS, then again every three to five years or after any change in taste, color, or plumbing.
Counties near Jefferson County
Closest first. Groundwater does not stop at a line on a map, so the next county over is a fair second opinion.
Want the numbers themselves? Download the Florida dataset as CSV, every county and town, with the sources named.
Sources
- USGS Water Quality Portal: 446 samples in Jefferson County. Data from the Water Quality Portal, a service of USGS, EPA and USDA; groundwater samples collected by USGS and cooperators. Retrieved September 3, 2026.
- USGS national arsenic model (Ayotte 2017): estimated share of 8,811 people on private wells in Jefferson County above 10 ug/L of arsenic, from geology, well depth and land use. County estimates of domestic well users with arsenic above 10 ug/L from the USGS national logistic regression model (Ayotte, Medalie and Qi, 2017), with private well population from the USGS 2015 county water-use compilation (Dieter and others, 2018). Retrieved September 15, 2026.
- FDEP regulated sites: 149 regulated sites located in Jefferson County. Petroleum contamination discharges and cleanup sites from the Florida Department of Environmental Protection. Retrieved September 17, 2026.
Non-detects count as samples and are treated as zero when computing medians. Exactly at the limit counts as not above it. A sample belongs to the town containing the well's reported coordinates.