Gallatin County, MT
These figures come from wells tested in Gallatin County, MT, not from any one well.
- Iron, manganese and sulfate are not common in wells in Gallatin County, MT (1 of 226, 0 of 209 and 11 of 267 tested wells were over). Only a test tells you about your own well.
- Wells in Gallatin County, MT are typically very hard (240 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
- 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. 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 | 0.4% |
| Wells over the level / wells judged | 1 of 226 |
| Median | < 0.03 mg/L |
| Years sampled | 1951–2016 |
| Wells | 226 |
| Test results | 432 |
| Wells left out | 0 |
| Sources | MTWTRSHD_WQX (226), USGS (169) |
More than half the wells had results below the lab's detection limit, so the median is reported as below that limit.
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 209 |
| Median | < 0.01 mg/L |
| Years sampled | 1976–2013 |
| Wells | 209 |
| Test results | 369 |
| Wells left out | 0 |
| Sources | MTWTRSHD_WQX (203), USGS (144), MTVOLWQM_WQX (6) |
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 | 54% |
| Median | 188.5 mg/L as CaCO₃ |
| Years sampled | 1951–2016 |
| Wells | 240 |
| Test results | 286 |
| Wells left out | 0 |
| Sources | USGS (219), MTWTRSHD_WQX (16), MTVOLWQM_WQX (5) |
Sulfate Recent
| Level it's compared with | 250 mg/L |
|---|---|
| Share of wells over the level | 4.1% |
| Wells over the level / wells judged | 11 of 267 |
| Median | 20.1 mg/L |
| Years sampled | 1951–2022 |
| Wells | 267 |
| Test results | 312 |
| Wells left out | 0 |
| Sources | USGS (220), MT305B_SECONDARYDATA (21), MONT_DEQ_WQX (20), MTVOLWQM_WQX (6) |