Duval County, FL
These figures come from wells tested in Duval County, FL, not from any one well.
- Iron is common in wells in Duval County, FL (17 of 51 tested wells were over that level), so it's worth testing for.
- Manganese is common in wells in Duval County, FL (5 of 41 tested wells were over that level), so it's worth testing for.
- Sulfate is not common in wells in Duval County, FL (1 of 120 tested wells were over). Only a test tells you about your own well.
- Wells in Duval County, FL are typically very hard (120 wells tested).
- Only a test of your own well tells you about your water.
What to test for
Start with the four this site covers:
- iron (common in wells here)
- manganese (common in wells here)
- hardness
- sulfate
Most well owners also test for these. We point to the source and don't interpret the results.
- arsenic: occurs naturally in groundwater in many regions. USGS: arsenic and drinking water
- nitrate: common near farmland and septic systems. EPA: private drinking water wells
- total coliform bacteria: the standard yearly well check. EPA: private drinking water wells
- lead and copper: from household plumbing, especially when pH is below 6.5. EPA: lead in drinking water
- PFAS: several states run private-well sampling programs. EPA: PFAS
- a certified lab: states certify labs and some run their own private-well programs. Florida's certified-lab list (from your state drinking-water program)
The numbers
County figures describe the wells sampled there, not any one well. Exact counts, sample years and sources are below.
Iron Recent
| Level it's compared with | 0.3 mg/L |
|---|---|
| Share of wells over the level | 33% |
| Wells over the level / wells judged | 17 of 51 |
| Median | 0.038 mg/L |
| Years sampled | 1925–2024 |
| Wells | 51 |
| Test results | 264 |
| Wells left out | 75 |
| Sources | USGS (57), 21FLSJWM_WQX (20), 21FLGW_WQX (14) |
Manganese Recent
| Level it's compared with | 0.05 mg/L |
|---|---|
| Share of wells over the level | 12% |
| Wells over the level / wells judged | 5 of 41 |
| Median | 0.0017 mg/L |
| Years sampled | 1952–2024 |
| Wells | 41 |
| Test results | 179 |
| Wells left out | 75 |
| Sources | USGS (26), 21FLSJWM_WQX (20), 21FLGW_WQX (14) |
Hardness Recent
| Level it's compared with | none; hardness is shown in bands |
|---|---|
| Share of wells very hard | 75% |
| Median | 250.75 mg/L as CaCO₃ |
| Years sampled | 1925–2024 |
| Wells | 120 |
| Test results | 1,496 |
| Wells left out | 75 |
| Sources | USGS (86), 21FLSJWM_WQX (20), 21FLGW_WQX (14) |
Sulfate Recent
| Level it's compared with | 250 mg/L |
|---|---|
| Share of wells over the level | 0.8% |
| Wells over the level / wells judged | 1 of 120 |
| Median | 100 mg/L |
| Years sampled | 1925–2024 |
| Wells | 120 |
| Test results | 1,127 |
| Wells left out | 37 |
| Sources | USGS (86), 21FLSJWM_WQX (20), 21FLGW_WQX (14) |