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Radon in Kalispell, Montana

EPA puts Flathead County, where Kalispell is, in Zone 1, its highest radon zone, and 37.8% of its 891 reported radon tests (2008 to 2017, laboratory totals) were at or above 4 pCi/L. Homes with elevated levels occur in all three zones, so only a test measures yours.

Data checked By Radon411Methodology

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  • Share at 4+ pCi/L

    37.8%

    7.7 pts below MT

    Flathead
    37.8%
    Montana
    45.5%

    Flathead, 22nd of 23 in MT, 2008 to 2017

  • Median result

    3.0pCi/L

    Below action level

    Flathead
    3.0 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of Flathead's tests, 2008 to 2017

  • Nearest county

    40.3%

    Lake, 41 miles

    Lake
    40.3%
    Flathead
    37.8%

    149 tests, 2008 to 2017

  • EPA radon zone

    Zone 1

    Highest potential

    1. Zone 1
    2. 2
    3. 3

    1 highest, 3 lowest

    Flathead, where Kalispell is

  • Tests reported

    891

    In Flathead

    Flathead
    891
    Lake
    149

    Reported to CDC before any fix, 2008 to 2017

Read a result for Kalispell

Starts at Flathead County's median, 3.0 pCi/L

3.0pCi/L

EPA’s own thresholds; the figures are the area’s, never this home’s.

EPA’s reading of 3.0 pCi/L

Between 2 and 4 pCi/L

  1. Under 20 to 1.9 pCi/L
  2. 2 to 4consider a fix
  3. 4 and aboveEPA says fix it

This result is between 2 and 4 pCi/L. EPA recommends considering a fix when the level is between 2 and 4 pCi/L. Flathead County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Kalispell, What is published

What is published for Kalispell

Information:

Every figure for Kalispell is a county's

Radon data is published by county, not by city, so for Kalispell it is Flathead County's: its EPA zone (Zone 1) and the 891 tests reported to CDC for 2008 to 2017, laboratory. Only a test tells you about one home.

Kalispell covers 12.4 square miles of land, all of it in Flathead County. About 31,851 people live there, 2,563 to the square mile.

Kalispell, Counties

The county Kalispell lies in

Measured

Flathead County's EPA zone and the figures CDC publishes for it, 2008 to 2017, laboratory.

Flathead CountyZone 1Highest predicted potential

37.8%
Reported tests at or above 4 pCi/L
3.0 pCi/L
Median reported result
891 tests
Tests reported to CDC
None
Yearly figures on file

Flathead County ranks 22nd of 23 Montana counties with 30 or more tests for that period, 7.7 points below the 45.5% pooled across Montana's counties, 2.1 points above the national pool of 35.7%.

Measured from the middle of Kalispell, the nearest counties with a CDC figure for 2008 to 2017, laboratory are Lake County (41 miles, 40.3% of 149 tests), Sanders County (53 miles, 50.0% of 38 tests) and Lincoln County (55 miles, 51.4% of 74 tests). Across the 8 nearest, the share at or above 4 pCi/L runs from 29.4% to 61.8%; the farthest of them, Cascade County, is 152 miles away at 29.4%.

No business in the directory gives Kalispell as its address; the Montana list covers it. Montana's other cities with a page of their own: Bozeman, Billings, Boulder and Helena.

The counties around Kalispell

By distance from the middle of Kalispell; counties with 30 or more tests.

Nearest counties to Kalispell with 30 or more tests
CountyDistanceTestsAt or above 4 pCi/LMedian
Lake County41 mi14940.3%2.9 pCi/L
Sanders County53 mi3850.0%4.0 pCi/L
Lincoln County55 mi7451.4%4.0 pCi/L
Mineral County80 mi3056.7%5.1 pCi/L
Missoula County84 mi2,61344.6%3.4 pCi/L
Lewis and Clark County118 mi46861.8%5.1 pCi/L
Ravalli County148 mi1,09044.6%3.5 pCi/L
Cascade County152 mi23529.4%1.7 pCi/L

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

Kalispell, Geology

The ground under Kalispell

Predicted

USGS's geologic map puts all of Kalispell's mapped land in one class: high radon potential. All of it lies in the area the map calls Northern Rocky Mountains, to which USGS gives a radon index of 13, in the high band (12 to 17).

USGS's geologic areas under Kalispell
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Northern Rocky MountainsGranitic, metaigneous, metasedimentary rocks, valley fill colluvium and alluvium.High13100%

Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.

Kalispell beside its county and Montana

All of Kalispell, like all of Flathead County, is rated high. Kalispell has more high-potential ground than Montana as a whole: 100% of its land against 78.5%.

Share of land by USGS radon potential: Kalispell, the county it lies in and Montana
AreaEPA zoneLow potentialModerate potentialHigh potential
KalispellBy countyNoneNone100%
Flathead CountyZone 1NoneNone100%
Montana56 counties, pooled by land areaVariesNone21.5%78.5%

The map rates the ground, not the air in any home.

Kalispell, Homes

Homes in Kalispell

Of Kalispell's 11,650 homes, 62% are detached houses, against 73% across Flathead County; 13% are in buildings of five or more homes. Half of its homes were built before 1984, close to Flathead County's 1989: 29% date from before 1960 and 32% from 2000 or later. 60% of occupied homes are lived in by their owner (Flathead County: 74%); in the rest a tenant can run a test, but a fix is the landlord's to make.

Homes in Kalispell, Flathead County, Montana, 2019 to 2023
HomesKalispellFlathead CountyMontana
Housing units11,65050,948522,939
Detached houses62%73%69%
In buildings of 5 or more13%8%9%
Mobile homes2%9%10%
Built before 196029%16%26%
Built since 200032%33%27%
Middle year built198419891980
Owner-occupied60%74%69%

Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.

Local help

Kalispell, Local resources

Local resources for Kalispell

Who to ask in Montana: its radon program, test kits and professionals.

The program's own words on licensing are on the Montana page.

What it means

Kalispell, Questions

Questions about radon in Kalispell

What radon zone is Kalispell in?

Kalispell takes its zone from Flathead County, which EPA puts in Zone 1, the map's highest class: a predicted county average above 4 pCi/L.

What are radon levels in Kalispell?

Around Kalispell, 37.8% of 891 tests reported from Flathead County for 2008 to 2017 (laboratory totals) reached 4 pCi/L or more, so a high result is no surprise here. The median reported result was 3.0 pCi/L.

Should I test my home in Kalispell?

Yes. Flathead County reported about 337 of its 891 tests at or above 4 pCi/L. That is below Montana's pooled 45.5%, and still not a reason to skip it, and ranks Flathead County 22nd of the 23 Montana counties with 30 or more tests. Which homes they were, no map can say. How to test a home.

What ground is Kalispell built on, as far as radon goes?

USGS's geologic map puts all of Kalispell on one named area, "Northern Rocky Mountains", rated high for radon potential, radon index 13.

Is radon higher in the counties around Kalispell?

It depends which way you go. 7 of the 8 nearest counties with a figure report a larger share than Flathead County's 37.8% and 1 a smaller one: from Cascade County (29.4%, 152 miles off) to Lewis and Clark County (61.8%, 118 miles off).

The answers use the published figures of Flathead County, the county Kalispell lies in.

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