About 24% of the county's 6,840 residents. Rank 32 of 56 in Montana.
95% range 91 to 304 private-well users (2010 base year). Rank 24 of 56 in Montana.
Highest potential (average indoor radon may be greater than 4 pCi/L). EPA says the map should not be used to decide whether an individual home needs testing.
Labs with an address in this county, from the official state lists on this site, matched by ZIP code.
What to test for in Powell County
Private wells are not regulated like public water: EPA advises owners to test their well every year for total coliform bacteria, nitrates, total dissolved solids and pH. Your state's own schedule:
- MSU Extension's Well Educated program calls a bacteria (coliform and E. coli) and nitrate test the minimum test recommended for all private well owners every year. For people who have not tested in recent years, or ever, it suggests a basic domestic analysis (alkalinity, bacteria, conductivity, nitrate and pH). source
Arsenic. USGS estimates that about 146 people using private wells in Powell County had arsenic above 10 µg/L, EPA's limit for public water (2010 base year; 95% range 91 to 304). USGS describes this kind of estimate as useful "for broad screening of the population at risk", so it says nothing certain about any one well. Arsenic has no taste or smell: test for it by name.
Radon. EPA puts Powell County in Zone 1: highest potential (average indoor radon may be greater than 4 pCi/L). That map is about radon in indoor air, and EPA says it should not be used to decide whether an individual home needs testing. If radon is found in your air and you have a well, EPA suggests testing the water too: see radon in well water.
For anything specific to your home (farms nearby, old plumbing, a new baby, a smell or stain), use the which-tests checklist. When the results arrive, check your numbers against EPA's limits.
Show the numbers
| Item | Value | Note |
|---|---|---|
| Missoula County | 4,888 people (2010 base year) | |
| Ravalli County | 3,257 people (2010 base year) | |
| Lewis and Clark County | 2,763 people (2010 base year) | |
| Flathead County | 2,633 people (2010 base year) | |
| Gallatin County | 1,472 people (2010 base year) | |
| Powell County (this county) | 146 people (2010 base year) |
USGS model estimate for broad screening, not a measurement of any well. Only a test tells you about your own well. Source: USGS, Estimated county level domestic well population with arsenic greater than 10 micrograms per liter (Ayotte, Medalie and Qi, 2017), accessed 2026-11-01.
Testing programs and help in Montana
- MSU Extension's Well Educated program helps well owners test and understand their water. Test kits are available at participating county offices, and guidance on what to test for comes with the kits. source
- MSU's 2026 Well Educated list shows where to pick up a kit. Most pickup points are county Extension offices; others include water quality districts, conservation districts and county environmental health departments. source
- MSU's Statewide Guidance by County map gives testing guidance based on location. Its statewide parameters of concern with exceedances are arsenic, fluoride, nitrate, selenium, uranium, lead and copper. MSU notes that lead and copper typically come from plumbing rather than groundwater. source
Buying a home with a well in Powell County
Loan test (FHA, VA, USDA) in Powell County, MT
- VA. Test results are valid for 90 days from the date the local health authority certifies them, unless the local authority says otherwise. VA’s chapter names no list of contaminants: the water must meet the local health authority’s requirements, or EPA guidelines where it has none. Your lender may ask for specific tests.
- FHA. A well test is required in the situations FHA’s handbook lists, among others, and the report may not be more than 180 days old at disbursement.
- USDA. Guaranteed loans need a water quality test for a private well, done by the local health authority or a state-certified lab, and no more than 180 days old at closing.
Lenders can ask for more (extra tests, a particular lab, who takes the sample): ask your lender before you book. Federal rules as read on Nov 3, 2026 source 1 source 2 source 3. Full comparison: VA, FHA and USDA well water test requirements. Loan test kits sold by mail, with price and days to results: kits compared.
State-certified labs in Powell County
None of the labs on our Montana list has an address in Powell County. Labs elsewhere in the state may take samples by mail or courier: ask the lab, and check the hold time for bacteria before you send one.
Testing by mail from Powell County. Montana State Environmental Laboratory, Chemistry Testing for Private Well sample submission form, July 2025 publishes these prices: Basic Screen (coliform and E. coli presence/absence, nitrate + nitrite, specific conductivity) $55; Metals Screen, WellScan (calcium, magnesium, hardness, sodium, lead, arsenic, copper, uranium) $135; Anion Screen (alkalinity, pH, fluoride, chloride, sulfate) $75 (checked 3 Nov 2026) source. All Montana state-lab prices and how to get a kit.
Labs on the Montana list whose own websites say they take homeowner samples: Alpine Analytical (Helena), Bridger Analytical Laboratory (Bozeman), DPHHS State of Montana Environmental Laboratory (Helena), Montana Environmental Laboratory (Kalispell). Use Check my ZIP to sort labs by distance.
See all Montana labs in the finder and filter by the test you need and by labs that take homeowner samples.
- USGS, Estimated use of water in the United States, county-level data for 2015 (Dieter et al., ver. 2.0, 2018)
- USGS, Estimated county level domestic well population with arsenic greater than 10 micrograms per liter (Ayotte, Medalie and Qi, 2017)
- U.S. EPA, Map of Radon Zones, county list (EPA 402/A-16/001)
- U.S. Census Bureau, 2020 ZCTA to county relationship file (lab ZIP codes to counties)
- Montana DPHHS Water Laboratory Certification Program - Certified Laboratories (page as fetched 2026-11-15 (no date printed))
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