Radon in Tennessee: radon map by county

EPA's Map of Radon Zones puts 39 of Tennessee's 95 counties in Zone 1 (predicted average indoor radon above 4 pCi/L), 32 in Zone 2 and 24 in Zone 3. Of 23,071 building tests that radon laboratories reported for 2008 to 2017, 32.8% were at or above EPA's 4 pCi/L action level, against 36.5% nationally (number 20 of 42 states with 1,000+ tests). The highest county share is Jefferson County (56.8% of 110 tests).

counties in Zone 1 (above 4 pCi/L predicted)

counties in Zone 2 (2 to 4)

counties in Zone 3 (below 2)

32.8%

of 23,071 lab tests at or above 4 pCi/L

Radon by county in Tennessee

EPA radon zone and radon test results for each county in Tennessee
County	EPA zone	Lab tests	Median	4+ pCi/L	TN agency data
Anderson County	Zone 1	195	3.8	48.3%	median 0.3 pCi/L, 8.7% of 46 (2025)
Bedford County	Zone 1	104	1.8	21%	median 2.8 pCi/L, 42.9% of 7 (2025)
Benton County	Zone 2	24	2.0	33.3%	median 1.9 pCi/L, 0% of 1 (2025)
Bledsoe County	Zone 3	28	2.1	24.3%	n/a
Blount County	Zone 1	550	3.4	42.8%	median 2.8 pCi/L, 38.9% of 36 (2025)
Bradley County	Zone 1	341	1.9	20.9%	median 2.6 pCi/L, 33.3% of 18 (2025)
Campbell County	Zone 3	51	4.5	53.5%	median 9.7 pCi/L, 75% of 12 (2025)
Cannon County	Zone 2	54	1.3	10.7%	median 0.7 pCi/L, 0% of 3 (2025)
Carroll County	Zone 3	18	1.0	20%	median 0.8 pCi/L, 0% of 2 (2025)
Carter County	Zone 2	284	3.7	47.2%	median 1.6 pCi/L, 18.2% of 33 (2025)
Cheatham County	Zone 2	162	2.3	34.1%	median 3.9 pCi/L, 50% of 2 (2025)
Chester County	Zone 2	39	1.1	0%	median 0.3 pCi/L, 0% of 3 (2025)
Claiborne County	Zone 1	86	3.3	44%	median 11.9 pCi/L, 50% of 2 (2025)
Clay County	Zone 2	37	2.3	34.8%	median 1.5 pCi/L, 25% of 4 (2025)
Cocke County	Zone 2	44	3.8	46.4%	median 6.7 pCi/L, 60% of 15 (2025)
Coffee County	Zone 2	168	1.3	16.5%	median 1.8 pCi/L, 30% of 10 (2025)
Crockett County	Zone 3	16	1.2	21.1%	median 2.0 pCi/L, 0% of 1 (2025)
Cumberland County	Zone 3	141	1.3	8.7%	median 1.8 pCi/L, 11.8% of 17 (2025)
Davidson County	Zone 1	3,946	2.6	36.4%	median 0.9 pCi/L, 16.5% of 613 (2025)
Decatur County	Zone 2	14	1.7	29.4%	median 2.6 pCi/L, 0% of 1 (2025)
DeKalb County	Zone 2	49	3.1	30.5%	median 0.7 pCi/L, 0% of 2 (2025)
Dickson County	Zone 2	160	2.1	26.3%	median 0.6 pCi/L, 9.1% of 22 (2025)
Dyer County	Zone 3	19	1.4	0%	median 1.8 pCi/L, 0% of 1 (2025)
Fayette County	Zone 3	86	1.1	11.1%	median 1.4 pCi/L, 0% of 3 (2025)
Fentress County	Zone 2	24	1.3	9.1%	median 0.9 pCi/L, 0% of 3 (2025)
Franklin County	Zone 3	220	2.1	25.6%	median 1.6 pCi/L, 33.3% of 6 (2025)
Gibson County	Zone 3	53	1.0	5.3%	median 0.7 pCi/L, 0% of 3 (2025)
Giles County	Zone 1	108	3.3	40.7%	median 3.3 pCi/L, 50% of 4 (2025)
Grainger County	Zone 1	41	3.8	48.2%	median 1.6 pCi/L, 28.6% of 7 (2025)
Greene County	Zone 1	317	3.6	46%	median 2.8 pCi/L, 32.4% of 37 (2025)
Grundy County	Zone 3	22	1.0	0%	median 0.3 pCi/L, 0% of 1 (2025)
Hamblen County	Zone 1	142	3.5	45.2%	median 5.6 pCi/L, 66.7% of 24 (2025)
Hamilton County	Zone 2	887	1.7	19.3%	median 0.7 pCi/L, 4.1% of 169 (2025)
Hancock County	Zone 1	20	1.8	9.1%	median 1.3 pCi/L, 0% of 2 (2025)
Hardeman County	Zone 3	5	1.6	20%	n/a
Hardin County	Zone 2	36	1.0	7.9%	n/a
Hawkins County	Zone 1	239	2.7	38.4%	median 1.3 pCi/L, 23.5% of 17 (2025)
Haywood County	Zone 3	14	0.7	0%	n/a
Henderson County	Zone 2	25	1.6	16.7%	n/a
Henry County	Zone 3	52	1.6	16.7%	median 2.0 pCi/L, 33.3% of 3 (2025)
Hickman County	Zone 1	96	2.2	35%	median 1.0 pCi/L, 0% of 2 (2025)
Houston County	Zone 2	10	2.8	28.6%	median 0.3 pCi/L, 0% of 1 (2025)
Humphreys County	Zone 1	81	2.0	23.8%	median 0.5 pCi/L, 3.9% of 51 (2025)
Jackson County	Zone 1	33	3.9	46.9%	median 5.7 pCi/L, 100% of 2 (2025)
Jefferson County	Zone 1	110	4.7	56.8%	median 3.9 pCi/L, 49% of 51 (2025)
Johnson County	Zone 2	129	2.3	34.4%	median 1.6 pCi/L, 0% of 1 (2025)
Knox County	Zone 1	1,771	2.5	33.6%	median 2.0 pCi/L, 25% of 148 (2025)
Lake County	Zone 3	6	1.0	0%	n/a
Lauderdale County	Zone 3	9	1.3	11.1%	median 1.6 pCi/L, 0% of 2 (2025)
Lawrence County	Zone 1	111	1.6	21.3%	median 3.6 pCi/L, 25% of 4 (2025)
Lewis County	Zone 1	47	1.4	16.1%	median 1.6 pCi/L, 0% of 1 (2025)
Lincoln County	Zone 1	113	1.9	20.8%	median 1.6 pCi/L, 33.3% of 6 (2025)
Loudon County	Zone 1	497	4.4	54.5%	median 2.6 pCi/L, 38.7% of 31 (2025)
Macon County	Zone 1	64	1.9	19.4%	median 1.6 pCi/L, 0% of 2 (2025)
Madison County	Zone 1	86	1.2	8.7%	median 0.9 pCi/L, 33.3% of 3 (2025)
Marion County	Zone 2	59	1.6	28.4%	median 1.5 pCi/L, 28.6% of 7 (2025)
Marshall County	Zone 1	115	1.6	18.1%	median 2.8 pCi/L, 50% of 2 (2025)
Maury County	Zone 3	377	3.0	39.3%	median 2.3 pCi/L, 22.7% of 22 (2025)
McMinn County	Zone 1	86	2.8	34%	median 2.6 pCi/L, 10% of 10 (2025)
McNairy County	Zone 2	58	1.0	8.5%	n/a
Meigs County	Zone 1	27	2.5	34.5%	n/a
Monroe County	Zone 1	136	3.5	45.5%	median 4.4 pCi/L, 55.6% of 9 (2025)
Montgomery County	Zone 2	445	2.3	33.8%	median 1.3 pCi/L, 18% of 128 (2025)
Moore County	Zone 1	36	2.9	35.3%	n/a
Morgan County	Zone 3	30	1.7	6.5%	median 1.3 pCi/L, 0% of 2 (2025)
Obion County	Zone 3	31	1.8	11.1%	n/a
Overton County	Zone 2	100	2.8	40.6%	median 3.0 pCi/L, 40% of 10 (2025)
Perry County	Zone 1	33	2.0	32.5%	n/a
Pickett County	Zone 2	33	3.5	46.5%	median 1.6 pCi/L, 0% of 2 (2025)
Polk County	Zone 2	35	2.2	27.9%	median 7.4 pCi/L, 50% of 2 (2025)
Putnam County	Zone 2	253	2.6	36%	median 2.9 pCi/L, 39.4% of 33 (2025)
Rhea County	Zone 3	43	2.4	26.7%	median 2.6 pCi/L, 0% of 4 (2025)
Roane County	Zone 1	192	2.5	33.7%	median 4.3 pCi/L, 60% of 10 (2025)
Robertson County	Zone 2	214	1.9	28.9%	median 0.9 pCi/L, 11.1% of 9 (2025)
Rutherford County	Zone 1	977	1.5	15.3%	median 0.8 pCi/L, 3.5% of 114 (2025)
Scott County	Zone 3	34	1.3	2.6%	median 0.9 pCi/L, 0% of 2 (2025)
Sequatchie County	Zone 3	51	1.9	20.7%	median 4.7 pCi/L, 66.7% of 6 (2025)
Sevier County	Zone 2	244	4.4	53%	median 2.2 pCi/L, 31% of 42 (2025)
Shelby County	Zone 3	319	1.0	6.3%	median 0.3 pCi/L, 0.8% of 126 (2025)
Smith County	Zone 1	48	3.1	45.5%	median 2.6 pCi/L, 33.3% of 9 (2025)
Stewart County	Zone 2	70	2.1	26.3%	median 1.2 pCi/L, 0% of 2 (2025)
Sullivan County	Zone 1	1,312	4.2	51.5%	median 2.8 pCi/L, 31.9% of 47 (2025)
Sumner County	Zone 2	1,039	1.9	26%	median 1.5 pCi/L, 13.6% of 103 (2025)
Tipton County	Zone 3	80	1.0	4.5%	median 1.0 pCi/L, 0% of 2 (2025)
Trousdale County	Zone 1	26	1.8	27.3%	n/a
Unicoi County	Zone 2	107	2.8	37.1%	median 1.7 pCi/L, 22.2% of 9 (2025)
Union County	Zone 1	44	2.1	37.7%	median 6.5 pCi/L, 60% of 5 (2025)
Van Buren County	Zone 2	16	2.1	40.9%	median 1.6 pCi/L, 0% of 1 (2025)
Warren County	Zone 2	123	3.0	36.9%	median 2.4 pCi/L, 33.3% of 6 (2025)
Washington County	Zone 1	1,196	3.9	49.6%	median 2.7 pCi/L, 42.6% of 68 (2025)
Wayne County	Zone 1	24	1.7	7.7%	median 23.8 pCi/L, 100% of 1 (2025)
Weakley County	Zone 3	15	1.1	12.5%	median 0.3 pCi/L, 0% of 1 (2025)
White County	Zone 2	116	3.9	49%	median 2.2 pCi/L, 38.9% of 18 (2025)
Williamson County	Zone 1	2,265	2.0	25.8%	median 1.6 pCi/L, 25.4% of 130 (2025)
Wilson County	Zone 1	678	1.7	20.2%	median 1.4 pCi/L, 24% of 50 (2025)

Lab tests: buildings tested by radon laboratories, 2008 to 2017; median in pCi/L; “4+ pCi/L” is the share of tests at or above EPA's action level. n/a: no value on file (no tests, or too few to report).

Tennessee state radon data

The state health department reports pre-mitigation tests reported in 2025, by county. The county pages show these results next to the laboratory results.

What the zones mean

Zone 1 counties have a predicted average indoor radon screening level above 4 pCi/L, Zone 2 from 2 to 4 pCi/L and Zone 3 below 2 pCi/L. The prediction is from 1993 indoor measurements, geology, aerial radioactivity, soils and foundation types. EPA: “This map should not be used to determine if individual homes need to be tested.” EPA recommends fixing a home at 4 pCi/L or more and considering a fix between 2 and 4 pCi/L, because there is no known safe level of exposure.

Radon in Tennessee: questions

What radon zone is Tennessee?

EPA's 1993 map does not give states one zone; it zones each county. In Tennessee, 39 counties are Zone 1, 32 Zone 2 and 24 Zone 3. EPA says the map "should not be used to determine if individual homes need to be tested".

Which Tennessee counties have the highest radon levels?

By the share of laboratory tests at or above 4 pCi/L for 2008 to 2017 (counties with 20 or more tests): Jefferson County 56.8% (median 4.7 pCi/L, 110 tests); Loudon County 54.5% (median 4.4 pCi/L, 497 tests); Campbell County 53.5% (median 4.5 pCi/L, 51 tests); Sevier County 53% (median 4.4 pCi/L, 244 tests); Sullivan County 51.5% (median 4.2 pCi/L, 1,312 tests).

How common is high radon in Tennessee?

32.8% of the 23,071 tests in the laboratory data for Tennessee (2008 to 2017) were at or above 4 pCi/L; the national share was 36.5%. Buildings are tested by choice, often because of a sale or a concern, so the share describes the tests on file, not every home.

Does Tennessee publish its own radon test data?

Yes. The state health department reports pre-mitigation tests reported in 2025, by county. Each Tennessee county page here shows those results beside the laboratory results.

Should I test for radon in Tennessee?

Yes. EPA recommends testing every home no matter where it is, fixing it at 4 pCi/L or more and considering a fix between 2 and 4 pCi/L, because there is no known safe level of radon exposure.

States bordering Tennessee

Radon in Alabama (13 of 67 in Zone 1)Radon in Arkansas (0 of 75 in Zone 1)Radon in Georgia (4 of 159 in Zone 1)Radon in Kentucky (30 of 120 in Zone 1)Radon in Mississippi (0 of 82 in Zone 1)Radon in Missouri (11 of 115 in Zone 1)Radon in North Carolina (8 of 100 in Zone 1)Radon in Virginia (62 of 133 in Zone 1)

Other free hazard lookups

All of these, plus wetlands, FEMA hazard ratings and the federal contamination lists, are in the Environmental Records Report for any US address ($29).

Superfund sites in Tennessee · Radon map of every state

Data compiled 2026-10-20. County-level screening information, not a radon measurement of any building.