Tennessee has significant radon risk, particularly in its eastern Appalachian counties. The Tennessee Department of Environment and Conservation estimates that approximately 30% of Tennessee homes have radon levels above 4.0 pCi/L statewide, with considerably higher percentages in Eastern Tennessee where the Appalachian geology creates elevated radon potential. Tennessee has enacted radon contractor licensing requirements.
EPA Radon Zone Designation
Eastern Tennessee counties overlying the Appalachian ridge and valley geology are Zone 1: Anderson, Blount, Bradley, Campbell, Claiborne, Cumberland, Grainger, Greene, Hamilton, Hawkins, Jefferson, Knox, Loudon, McMinn, Meigs, Monroe, Morgan, Polk, Rhea, Roane, Scott, Sevier, Sullivan, Union, and Washington counties. Middle and West Tennessee counties are generally Zone 2 to Zone 3.
Radon Contractor Licensing in Tennessee
Tennessee requires radon contractors to hold current NRPP or NRSB national certification, and Tennessee has additional state registration requirements for radon professionals. The Tennessee Department of Environment and Conservation administers radon program resources. Tennessee maintains a registry of radon measurement and mitigation service providers. Verify contractor credentials through TDEC and through the national NRPP/NRSB directories before hiring.
Radon Disclosure Requirements in Tennessee
Tennessee’s Residential Property Condition Disclosure Act requires sellers to disclose known material defects. The Tennessee disclosure form includes environmental conditions — sellers with knowledge of elevated radon test results should disclose them. Tennessee does not have a radon-specific disclosure statute, but the general material defect obligation applies. Radon testing is particularly important in Eastern Tennessee transactions.
Frequently Asked Questions
What parts of Tennessee have the highest radon?
Eastern Tennessee’s Appalachian counties — including Knox (Knoxville), Hamilton (Chattanooga), Bradley, Anderson, and surrounding ridge-and-valley counties — have the state’s highest radon potential. Middle and West Tennessee counties generally have lower levels.
Does Tennessee require radon contractor certification?
Tennessee requires NRPP or NRSB national certification and has additional state registration requirements. Verify credentials through TDEC and nrpp.info before hiring.
Should I test for radon in Knoxville or Chattanooga?
Yes. Both Knoxville (Knox County) and Chattanooga (Hamilton County) are in Zone 1 Appalachian counties. Radon testing is strongly recommended for all homes in Eastern Tennessee, and should be standard in real estate transactions in these areas.
Knoxville and Chattanooga Area Radon
Knox County (Knoxville) and Hamilton County (Chattanooga) are Zone 1 Appalachian counties where radon is a significant public health concern. The Knoxville metropolitan area — which includes Knox, Anderson, Blount, Loudon, Sevier, Union, and Grainger counties — sits within the Appalachian Valley and Ridge province where limestone, dolostone, and shale formations create both radon-producing geology and preferential pathways for radon migration into homes. The Tennessee Department of Environment and Conservation (TDEC) has documented elevated radon testing results throughout the Knoxville metro.
Tennessee Testing Resources
The Tennessee Department of Environment and Conservation Radon Program provides resources including information on certified contractors, radon testing guidance, and educational materials for homeowners. TDEC participates in EPA’s SIRG program. Tennessee also participates in the Appalachian Regional Radon Outreach Initiative, which coordinates radon awareness across Appalachian states. Contact TDEC directly for the current certified contractor list and any test kit assistance programs.
Radon in Nashville and Memphis
Davidson County (Nashville) is Zone 2 with moderate radon potential. The Nashville Basin’s limestone geology creates some radon risk, though lower than the Appalachian counties to the east. Shelby County (Memphis) is Zone 2 to Zone 3. Middle and West Tennessee homeowners should still test — the 30% statewide prevalence rate means elevated radon is found throughout Tennessee, not just in the eastern Appalachian counties.
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