Yellowstone County, MT
These figures come from wells tested in Yellowstone County, MT, not from any one well.
- Manganese is common in wells in Yellowstone County, MT (5 of 14 tested wells were over that level), so it's worth testing for.
- Sulfate is common in wells in Yellowstone County, MT (148 of 198 tested wells were over that level), so it's worth testing for.
- Iron is not common in wells in Yellowstone County, MT (1 of 12 tested wells were over). Only a test tells you about your own well.
- Wells in Yellowstone County, MT are typically very hard (199 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:
- manganese (common in wells here)
- sulfate (common in wells here)
- iron
- 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 | 8.3% |
| Wells over the level / wells judged | 1 of 12 |
| Median | 0.0055 mg/L |
| Years sampled | 1916–2012 |
| Wells | 12 |
| Test results | 196 |
| Wells left out | 0 |
| Sources | USGS (190) |
Manganese Recent
| Level it's compared with | 0.05 mg/L |
|---|---|
| Share of wells over the level | 36% |
| Wells over the level / wells judged | 5 of 14 |
| Median | 0.01399 mg/L |
| Years sampled | 1972–2012 |
| Wells | 14 |
| Test results | 152 |
| Wells left out | 0 |
| Sources | USGS (144), MTVOLWQM_WQX (2) |
Hardness Recent
| Level it's compared with | none; hardness is shown in bands |
|---|---|
| Share of wells very hard | 67% |
| Median | 340 mg/L as CaCO₃ |
| Years sampled | 1914–2012 |
| Wells | 199 |
| Test results | 207 |
| Wells left out | 0 |
| Sources | USGS (197), MTVOLWQM_WQX (2) |
Sulfate Recent
| Level it's compared with | 250 mg/L |
|---|---|
| Share of wells over the level | 75% |
| Wells over the level / wells judged | 148 of 198 |
| Median | 620 mg/L |
| Years sampled | 1914–2012 |
| Wells | 198 |
| Test results | 206 |
| Wells left out | 0 |
| Sources | USGS (196), MTVOLWQM_WQX (2) |