Stillwater County, MT
These figures come from wells tested in Stillwater County, MT, not from any one well.
- Sulfate is common in wells in Stillwater County, MT (31 of 62 tested wells were over that level), so it's worth testing for.
- Iron and manganese are not common in wells in Stillwater County, MT (0 of 19 and 0 of 20 tested wells were over). Only a test tells you about your own well.
- Wells in Stillwater County, MT are typically very hard (62 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:
- sulfate (common in wells here)
- iron
- manganese
- 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. Montana'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 | 0.0% |
| Wells over the level / wells judged | 0 of 19 |
| Median | 0.012 mg/L |
| Years sampled | 1974–2005 |
| Wells | 19 |
| Test results | 79 |
| Wells left out | 15 |
| Sources | USGS (39), MBMG_WQX (19) |
Manganese Recent
| Level it's compared with | 0.05 mg/L |
|---|---|
| Share of wells over the level | 0.0% |
| Wells over the level / wells judged | 0 of 20 |
| Median | < 0.01 mg/L |
| Years sampled | 1974–2009 |
| Wells | 20 |
| Test results | 80 |
| Wells left out | 15 |
| Sources | USGS (39), MBMG_WQX (19), MTVOLWQM_WQX (1) |
More than half the wells had results below the lab's detection limit, so the median is reported as below that limit.
Hardness Recent
| Level it's compared with | none; hardness is shown in bands |
|---|---|
| Share of wells very hard | 66% |
| Median | 304.106 mg/L as CaCO₃ |
| Years sampled | 1929–2009 |
| Wells | 62 |
| Test results | 83 |
| Wells left out | 15 |
| Sources | USGS (42), MBMG_WQX (19), MTVOLWQM_WQX (1) |
Sulfate Recent
| Level it's compared with | 250 mg/L |
|---|---|
| Share of wells over the level | 50% |
| Wells over the level / wells judged | 31 of 62 |
| Median | 250.5 mg/L |
| Years sampled | 1929–2009 |
| Wells | 62 |
| Test results | 83 |
| Wells left out | 15 |
| Sources | USGS (42), MBMG_WQX (19), MTVOLWQM_WQX (1) |