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Radon in Fargo, North Dakota

EPA puts Cass County, where Fargo is, in Zone 1, its highest radon zone, and high results are common there: 57.5% of the 862 radon tests reported to CDC (2008 to 2017, laboratory totals) came back 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

How to test this homeFind a certified tester

  • Share at 4+ pCi/L

    57.5%

    1.8 pts below ND

    Cass
    57.5%
    ND
    59.3%

    Cass, 20th of 29 in ND, 2008 to 2017

  • Median result

    4.7pCi/L

    Action level reached

    Cass
    4.7 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of Cass's tests, 2008 to 2017

  • Nearest county

    43.0%

    Richland, 42 miles

    Richland
    43.0%
    Cass
    57.5%

    93 tests, 2008 to 2017

  • EPA radon zone

    Zone 1

    Highest potential

    1. Zone 1
    2. 2
    3. 3

    1 highest, 3 lowest

    Cass, where Fargo is

  • Tests reported

    862

    In Cass

    Cass
    862
    Richland
    93

    Reported to CDC before any fix, 2008 to 2017

Read a result for Fargo

Starts at Cass County's median, 4.7 pCi/L

4.7pCi/L

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

EPA’s reading of 4.7 pCi/L

At or above 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 at or above 4 pCi/L. EPA recommends fixing a home when the radon level is 4 pCi/L or higher. Cass County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Fargo, What is published

What is published for Fargo

Information:

Every figure for Fargo is a county's

Radon data is published by county, not by city, so for Fargo it is Cass County's: its EPA zone (Zone 1) and the 862 tests reported to CDC for 2008 to 2017, laboratory. Only a test tells you about one home.

Fargo covers 49.8 square miles of land, all of it in Cass County. About 136,275 people live there, 2,736 to the square mile.

Fargo, Counties

The county Fargo lies in

Measured

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

Cass CountyZone 1Highest predicted potential

57.5%
Reported tests at or above 4 pCi/L
4.7 pCi/L
Median reported result
862 tests
Tests reported to CDC
None
Yearly figures on file

Cass County ranks 20th of 29 North Dakota counties with 30 or more tests for that period, 1.8 points below the 59.3% pooled across North Dakota's counties, 21.8 points above the national pool of 35.7%.

Measured from the middle of Fargo, the nearest counties with a CDC figure for 2008 to 2017, laboratory are Richland County (42 miles, 43.0% of 93 tests), Traill County (44 miles, 51.4% of 37 tests) and Ransom County (48 miles, 61.6% of 151 tests). Across the 8 nearest, the share at or above 4 pCi/L runs from 43.0% to 75.9%; the farthest of them, Stutsman County, is 101 miles away at 73.5%.

The directory lists 3 businesses with an address in Fargo, 3 for testing and 2 for mitigation. North Dakota's other cities with a page of their own: Bismarck.

The counties around Fargo

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

Nearest counties to Fargo with 30 or more tests
CountyDistanceTestsAt or above 4 pCi/LMedian
Richland County42 mi9343.0%3.6 pCi/L
Traill County44 mi3751.4%4.1 pCi/L
Ransom County48 mi15161.6%5.8 pCi/L
Barnes County59 mi8367.5%5.6 pCi/L
Grand Forks County79 mi68075.9%8.8 pCi/L
LaMoure County86 mi4470.5%5.2 pCi/L
Dickey County95 mi7067.1%4.8 pCi/L
Stutsman County101 mi35173.5%5.8 pCi/L

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

Fargo, Geology

The ground under Fargo

Predicted

USGS's geologic map puts all of Fargo's mapped land in one class: high radon potential. 98.9% of it lies in the area the map calls Glacial Lakes, to which USGS gives a radon index of 14, in the high band (12 to 17).

USGS's geologic areas under Fargo
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Glacial LakesSilt and clay deposits of Glacial Lake Agassiz derived from Cretaceous shales containing higher than average amounts of uranium.High1498.9%
Lake Agassiz PlainSilt and clay deposits of Glacial Lake Agassiz derived from Cretaceous shales containing higher than average amounts of uranium.High151.1%

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

Fargo beside its county and North Dakota

All of Fargo, like all of Cass County, is rated high. On high-potential ground Fargo is close to North Dakota as a whole: 100% of its land against 98.9%.

Share of land by USGS radon potential: Fargo, the county it lies in and North Dakota
AreaEPA zoneLow potentialModerate potentialHigh potential
FargoBy countyNoneNone100%
Cass CountyZone 1NoneNone100%
North Dakota53 counties, pooled by land areaVariesNone1.1%98.9%

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

Fargo, Homes

Homes in Fargo

Fargo has 63,177 homes, and many share a building: 49% are in buildings of five or more, 35% are detached houses, against 43% across Cass County. Half of its homes were built before 1991, close to Cass County's 1993: 18% date from before 1960 and 36% from 2000 or later. Most occupied homes here are rented: owners live in 44% (Cass County: 52%). A tenant can run a test; a fix is the landlord's to make.

Homes in Fargo, Cass County, North Dakota, 2019 to 2023
HomesFargoCass CountyNorth Dakota
Housing units63,17787,497374,866
Detached houses35%43%57%
In buildings of 5 or more49%40%25%
Mobile homes2%2%7%
Built before 196018%16%24%
Built since 200036%40%31%
Middle year built199119931981
Owner-occupied44%52%63%

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

Local help

Fargo, Professionals

Radon professionals listed in Fargo

Businesses whose listed city is Fargo, from the state registries and listings in the Radon411 directory, with the same business and certification status the directory shows.

3 listings with Fargo as the city. See radon mitigation and testing in Fargo, or all radon professionals in North Dakota.

Fargo, Local resources

Local resources for Fargo

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

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

What it means

Fargo, Questions

Questions about radon in Fargo

What radon zone is Fargo in?

Fargo has no zone of its own: it shares Cass County's, Zone 1, the map's highest class: a predicted county average above 4 pCi/L.

What are radon levels in Fargo?

High results are ordinary around Fargo: 57.5% of the 862 tests reported from Cass County for 2008 to 2017 (laboratory totals) were at or above 4 pCi/L, the level at which EPA says to fix a home. The median reported result was 4.7 pCi/L.

Should I test my home in Fargo?

Yes. Cass County reported about 496 of its 862 tests at or above 4 pCi/L. That is about what North Dakota as a whole reports (59.3%), and ranks Cass County 20th of the 29 North Dakota counties with 30 or more tests. Which homes they were, no map can say. How to test a home.

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

USGS's geologic map puts all of Fargo on one named area, "Glacial Lakes", rated high for radon potential, radon index 14.

Is radon higher in the counties around Fargo?

It depends which way you go. 6 of the 8 nearest counties with a figure report a larger share than Cass County's 57.5% and 2 a smaller one: from Richland County (43.0%, 42 miles off) to Grand Forks County (75.9%, 79 miles off).

Who tests for or fixes radon in Fargo?

Fargo is the address of 3 businesses in Radon411's directory, 3 listed for testing and 2 for mitigation. Each entry names the public list it came from. Radon professionals in Fargo.

The answers use the published figures of Cass County, the county Fargo lies in.

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