Typical values from 52 sampled wells in Putnam County · Full groundwater profile
What Are You Noticing in Your Water?
Pre-selected from Putnam 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 Putnam County and nearby counties
Putnam County has a high rate of private well reliance in Northeast Florida, with 70.8% of built parcels drawing drinking water from an onsite well rather than a public utility, according to the Florida Department of Health.
Putnam County is a historic St. Johns River port county, and like the rest of this region, its groundwater comes from the Floridan Aquifer, a limestone formation that shapes which well water problems show up most often here.
In this guide
Groundwater Profile: Putnam County
Most groundwater pumped in Putnam County comes from the Floridan Aquifer (USGS, 2015 withdrawals). Across 52 sampled wells, the median hardness is 7.1 gpg, which the USGS classes as hard. It applies to wells across Putnam County, including around Palatka, Crescent City and Interlachen.
What shows up in local well samples:
- HardnessMedian 7.1 gpg; 50% of 52 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 0 Putnam 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 Putnam County Compares to Florida and the U.S.
See How Putnam County Compares to Florida & the US
| Share of wells with… | Putnam CountyPutnam | FloridaFL | United StatesUS |
|---|---|---|---|
| Hard water (above 7 gpg) | 50% | 79% | 60% |
| Iron above 0.3 mg/L | 40% | 35% | 19% |
| Manganese above 0.05 mg/L | 4% | 8% | 21% |
| Dissolved solids above 500 mg/L | 17% | 22% | 15% |
| Acidic water (pH below 6.5) | 29% | 15% | 14% |
| Nitrate above 10 mg/L (EPA limit) | Limited data | 2% | 4% |
| Arsenic above 10 µg/L (EPA limit) | 2% | 3% | 7% |
| Median hardness | 7.1 gpg | 12.4 gpg | — |
| Median pH | 7.6 | 7.2 | 7.3 |
Putnam 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 Putnam County well needs
Opens the diagnostic calculator with Putnam County median values (7.1 gpg hardness, 0.04 ppm iron, pH 7.6) for a 3–4 person home. Swap in your own lab results for an exact plan.
Testing Your Well in Putnam County
The Florida Department of Health in Putnam 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 Putnam 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 Putnam 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
Putnam County borders these counties with published reports:
Alachua County
11.5 gpg hardness · HardnessBradford County
9.3 gpg hardness · Hardness, IronClay County
4.8 gpg hardnessMarion County
9.9 gpg hardness · Hardness, Hydrogen sulfideSt. Johns County
23.2 gpg hardness · Hardness, Chloride (salinity)Volusia County
16.1 gpg hardness · Hardness, Chloride (salinity)Frequently Asked Questions
How hard is well water in Putnam County?
Groundwater samples from 52 wells in Putnam County have a median hardness of 7.1 grains per gallon (121 mg/L), which the USGS classes as hard. About 50% 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 Putnam County well water?
The median iron level across 52 sampled wells is 0.04 mg/L, below the EPA aesthetic guideline of 0.3 mg/L, and 40% 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 Putnam County?
Hydrogen sulfide (the rotten-egg smell) was measured in only 0 Putnam 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 Putnam County?
Most groundwater pumped in Putnam County comes from the Floridan Aquifer (USGS, 2015 withdrawals).
Does boiling well water make it safe to drink in Putnam 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.
Why does Putnam County have so many private wells?
Rural counties like Putnam often fall outside the service area of any municipal water utility, so new homes are built with an onsite well by default. The Florida Department of Health’s 2022 parcel mapping found 70.8% of built parcels here on private wells.
Do I need to test my well water if my neighbors say theirs is fine?
Yes. Well depth, casing condition, and the exact aquifer layer tapped can vary block to block, so one neighbor’s clean test does not guarantee another’s. A full annual test is the only reliable way to know what is in your own water.
Is Floridan Aquifer water generally safe to drink untreated?
Much of it is chemically safe but aesthetically unpleasant (hard, sulfur-smelling, or iron-stained), which is why treatment here is usually about comfort and plumbing protection rather than an acute health risk. A lab test is still the only way to rule out bacteria, nitrates, or other contaminants specific to your well.
Written by Well Water Advisor Editorial Team.