Johnson County, IA
These figures come from wells tested in Johnson County, IA, not from any one well.
- Iron is common in wells in Johnson County, IA (4 of 10 tested wells were over that level), so it's worth testing for.
- Manganese is common in wells in Johnson County, IA (2 of 10 tested wells were over that level), so it's worth testing for.
- Sulfate is common in wells in Johnson County, IA (35 of 104 tested wells were over that level), so it's worth testing for.
- Wells in Johnson County, IA are typically very hard (105 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)
- sulfate (common in wells here)
- hardness
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. Iowa'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 | 40% |
| Wells over the level / wells judged | 4 of 10 |
| Median | 0.00535 mg/L |
| Years sampled | 1934–2017 |
| Wells | 10 |
| Test results | 194 |
| Wells left out | 12 |
| Sources | USGS (104) |
Manganese Recent
| Level it's compared with | 0.05 mg/L |
|---|---|
| Share of wells over the level | 20% |
| Wells over the level / wells judged | 2 of 10 |
| Median | 0.0027025 mg/L |
| Years sampled | 1934–2017 |
| Wells | 10 |
| Test results | 193 |
| Wells left out | 12 |
| Sources | USGS (102) |
Hardness Recent
| Level it's compared with | none; hardness is shown in bands |
|---|---|
| Share of wells very hard | 100% |
| Median | 430 mg/L as CaCO₃ |
| Years sampled | 1934–2017 |
| Wells | 105 |
| Test results | 197 |
| Wells left out | 12 |
| Sources | USGS (105) |
Sulfate Recent
| Level it's compared with | 250 mg/L |
|---|---|
| Share of wells over the level | 34% |
| Wells over the level / wells judged | 35 of 104 |
| Median | 72.85 mg/L |
| Years sampled | 1934–2017 |
| Wells | 104 |
| Test results | 196 |
| Wells left out | 11 |
| Sources | USGS (104) |