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Locations and reports

Radon in Helena, Montana

Helena, Montana lies in Lewis and Clark County, which EPA places in Zone 1, highest predicted potential. Radon data is published by county, so this page reads Lewis and Clark County's figures.

MontanaAbout 35,138 people

What this means for you

  • Your area: EPA rates Lewis and Clark County, where Helena is, Zone 1, the highest of its three radon zones. That is a prediction for the whole county, and homes with elevated levels occur in all three zones.
  • Local tests: Of 468 radon tests reported to CDC for Lewis and Clark County (2008 to 2017, laboratory), 61.8% were at or above 4 pCi/L, EPA's action level.
  • Your home: The only way to know your home’s level is to test it.
How to testFind a certified tester

pCi/L (picocuries per liter) is the unit radon is measured in. EPA recommends fixing a home at 4 pCi/L or above, its action level.

Helena, What is published

What is published for Helena

Information:

Radon data is published by county, not by city

Radon data is published by county, not by city. EPA assigns radon zones to counties, and CDC publishes radon test figures by county. Neither publishes a figure for Helena, so every radon figure on this page belongs to a county and is labelled with it. Only a test tells you about one home.

Lewis and Clark County has an EPA zone and its own CDC test figures, shown below. About 35,138 people live in Helena.

Helena, Counties

The county Helena lies in

Measured

Each county's own EPA zone and its own published CDC figures for 2008 to 2017, laboratory, the newest period any of them has. A county without a figure for that period is shown without one, never with a figure from another year.

Lewis and Clark CountyZone 1Highest predicted potential

61.8%
Reported tests at or above 4 pCi/L, 2008 to 2017, laboratory
5.1 pCi/L
Median reported result
468 tests
Tests reported to CDC
0
Annual years on file

The median reported pre-mitigation result for 2008 to 2017, laboratory was 5.1 pCi/L in Lewis and Clark County.

CDC counts radon tests that were reported to it, not homes, and figures from few tests can swing widely from year to year. Each county’s report has its full history.

Predicted: EPA Map of Radon Zones, by county. Measured: CDC tracking data, by county, 2008 to 2017, laboratory.

Helena, Local resources

Local resources for Helena

Who to ask in Montana: the state's radon program, test kits and professionals.

Radon Control Program

Montana DEQ

Montana’s radon program answers questions about testing, mitigation and the rules where you live.

Phone
1-800-546-0483
Licensing of radon professionals
Montana DEQ does not certify or require proof of certification for the contractors listed.
Visit the program's page(opens in a new tab)

Test kits

The program says: Energy Bureau staff manage the radon information toll-free hotline and distribute subsidized radon test kits to Montana residents.

Free and low-cost kitsCompare kits

Radon professionals

Radon testers and mitigators in Montana, each with how its listing was checked.

Professionals in Montana

Helena, Questions

Questions about radon in Helena

What radon zone is Helena in?

EPA's Map of Radon Zones classifies counties, not cities. Lewis and Clark County is in Zone 1 (highest predicted potential). A zone is a prediction for a whole county and never tells you the level in one home.

How many radon tests come back high in Helena's counties?

For 2008 to 2017, laboratory, the share of radon tests reported to CDC that were at or above 4 pCi/L was 61.8% in Lewis and Clark County (468 tests). Each is that county's own figure, counting tests reported to CDC, not homes. Radon411 does not average or combine them into a figure for the city.

Should I test my home in Helena?

Yes. Testing is the only way to know the radon level in a specific building. EPA recommends fixing a home when the radon level is 4 pCi/L or higher. EPA recommends considering a fix when the level is between 2 and 4 pCi/L. How to test a home.

The answers use the published figures of Lewis and Clark County, the county Helena lies in.

Helena, Keep reading

Keep reading

Helena / Next steps

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