Typical values from 33 sampled wells in Nassau County · Full groundwater profile
What Are You Noticing in Your Water?
Pre-selected from Nassau County well data. Untick anything you do not notice in your own water.
Based on the contaminants most commonly reported in this region. Always confirm with a certified lab water test before buying equipment.
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Explore Nassau County and nearby counties
A large share of homes in Nassau County, in Northeast Florida, rely on private wells: 37.9% of built parcels, roughly 15,281 properties,, according to the Florida Department of Health's 2022 inventory.
Most groundwater pumped in Nassau County comes from the Floridan Aquifer (USGS, 2015 withdrawals). Samples from 33 local wells put the median hardness at 17.1 gpg (very hard) and median iron at 0.02 mg/L. The county's largest communities are Yulee, Fernandina Beach and Nassau Village-Ratliff.
In this guide
Groundwater Profile: Nassau County
Most groundwater pumped in Nassau County comes from the Floridan Aquifer (USGS, 2015 withdrawals). Across 33 sampled wells, the median hardness is 17.1 gpg, which the USGS classes as very hard. It applies to wells across Nassau County, including around Fernandina Beach, Hilliard and Callahan.
What shows up in local well samples:
- HardnessMedian 17.1 gpg; 100% of 33 sampled wells above 7 gpg
Calcium and magnesium dissolved from limestone. Leaves scale on fixtures and water heaters and reduces soap lather. Not a health risk.
Water softener sizing
Hydrogen sulfide (the rotten-egg smell) was measured in only 1 Nassau County wells, too few to say how common it is. Limited local data (fewer than 20 samples): individual well testing recommended. If you notice the smell, a sulfide test confirms it.
How Nassau County Compares to Florida and the U.S.
See How Nassau County Compares to Florida & the US
| Share of wells with… | Nassau CountyNassau | FloridaFL | United StatesUS |
|---|---|---|---|
| Hard water (above 7 gpg) | 100% | 79% | 60% |
| Iron above 0.3 mg/L | 19% | 35% | 19% |
| Manganese above 0.05 mg/L | 16% | 8% | 21% |
| Dissolved solids above 500 mg/L | 12% | 22% | 15% |
| Acidic water (pH below 6.5) | 0% | 15% | 14% |
| Nitrate above 10 mg/L (EPA limit) | Limited data | 2% | 4% |
| Arsenic above 10 µg/L (EPA limit) | 0% | 3% | 7% |
| Median hardness | 17.1 gpg | 12.4 gpg | — |
| Median pH | 7.4 | 7.2 | 7.3 |
Nassau County and Florida: share of sampled wells (all well types, samples since 2000) whose typical value exceeds the level, from the Water Quality Portal. United States: USGS Circular 1332, about 2,100 domestic wells in 48 states sampled 1991 to 2004. Well types and years differ, so read this as a broad comparison. Highlighted cells are well above the national share.
See what a typical Nassau County well needs
Opens the diagnostic calculator with Nassau County median values (17.1 gpg hardness, 0.02 ppm iron, pH 7.4) for a 3–4 person home. Swap in your own lab results for an exact plan.
Testing Your Well in Nassau County
The Florida Department of Health in Nassau County oversees private well permitting in the county and investigates suspected contamination. For routine bacteria, nitrate or full-panel tests, use a laboratory certified by the Florida Department of Health.
What to test for in Nassau County:
- Bacteria (total coliform and E. coli) and nitrate, at least once a year (Florida Department of Health recommendation)
- Hardness in grains per gallon (gpg) to size a softener
- After any flood, new well work or a change in taste, color or smell
The Florida Department of Health in Nassau County can explain how to collect samples and where to send them. Statewide guidance is on the FDOH private well testing page, and our guide to how to test well water covers which tests to order.
Nearby Counties
Nassau County borders these counties with published reports:
Frequently Asked Questions
How many homes in Nassau County use private wells?
The Florida Department of Health’s Florida Water Management Inventory (2022 data) found 37.9% of built parcels in Nassau County on private wells, roughly 15,281 properties.
How hard is well water in Nassau County?
Groundwater samples from 33 wells in Nassau County have a median hardness of 17.1 grains per gallon (292 mg/L), which the USGS classes as very hard. About 100% of sampled wells are above 7 gpg, the point where a water softener is usually worthwhile. The Florida statewide median is 12.4 gpg.
Is iron a problem in Nassau County well water?
The median iron level across 32 sampled wells is 0.02 mg/L, below the EPA aesthetic guideline of 0.3 mg/L, and 19% of wells exceed it. Most wells will not stain, but if yours does, a lab test tells you whether iron or manganese is the cause.
Why does my well water smell like rotten eggs in Nassau County?
Hydrogen sulfide (the rotten-egg smell) was measured in only 1 Nassau County wells, too few to say how common it is. Limited local data (fewer than 20 samples): individual well testing recommended. If you notice the smell, a sulfide test confirms it. The smell is a nuisance rather than a health risk at typical levels.
Which aquifer supplies wells in Nassau County?
Most groundwater pumped in Nassau County comes from the Floridan Aquifer (USGS, 2015 withdrawals).
Does boiling well water make it safe to drink in Nassau County?
Only if bacteria are the problem. A one-minute rolling boil kills germs, but it does not remove nitrate, arsenic or other chemicals, and it concentrates them as water evaporates. Test first, and see our boiling well water myth buster for when boiling helps.
How often should I test my well water in Nassau County?
The Florida Department of Health recommends testing private wells for bacteria and nitrate at least once a year, and again after flooding or well repairs. The Florida Department of Health in Nassau County can explain how to collect and submit samples.
Written by Well Water Advisor Editorial Team.