Collier County, FL
These figures come from wells tested in Collier County, FL, not from any one well.
- Iron is common in wells in Collier County, FL (91 of 265 tested wells were over that level), so it's worth testing for.
- Manganese and sulfate are not common in wells in Collier County, FL (11 of 265 and 28 of 419 tested wells were over). Only a test tells you about your own well.
- Wells in Collier County, FL are typically very hard (426 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
- 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 | 34% |
| Wells over the level / wells judged | 91 of 265 |
| Median | 0.1 mg/L |
| Years sampled | 1923–2026 |
| Wells | 265 |
| Test results | 2,366 |
| Wells left out | 11 |
| Sources | 21FLCOLL_WQX (196), USGS (129), 21FLGW_WQX (49), 21FLSFWM (3) |
Manganese Recent
| Level it's compared with | 0.05 mg/L |
|---|---|
| Share of wells over the level | 4.2% |
| Wells over the level / wells judged | 11 of 265 |
| Median | 0.00493 mg/L |
| Years sampled | 1955–2026 |
| Wells | 265 |
| Test results | 2,224 |
| Wells left out | 10 |
| Sources | 21FLCOLL_WQX (196), 21FLGW_WQX (49), USGS (49), 21FLSFWM (2) |
Hardness Recent
| Level it's compared with | none; hardness is shown in bands |
|---|---|
| Share of wells very hard | 84% |
| Median | 305 mg/L as CaCO₃ |
| Years sampled | 1901–2026 |
| Wells | 426 |
| Test results | 2,669 |
| Wells left out | 11 |
| Sources | 21FLCOLL_WQX (196), USGS (177), 21FLGW_WQX (49), 21FLSFWM (4) |
Sulfate Recent
| Level it's compared with | 250 mg/L |
|---|---|
| Share of wells over the level | 6.7% |
| Wells over the level / wells judged | 28 of 419 |
| Median | 14 mg/L |
| Years sampled | 1901–2026 |
| Wells | 419 |
| Test results | 2,665 |
| Wells left out | 9 |
| Sources | 21FLCOLL_WQX (195), USGS (175), 21FLGW_WQX (49) |