Montana
For Montana, disclosure required is Yes; sellers must provide a disclosure statement regarding adverse material facts including whether the property has been tested or treated for radon. Must also provide a general radon warning statement and disclosure of known radon test results; testing mandated is No mandatory residential testing requirement; professional certification required is Yes; radon professionals must pass a U.S. EPA proficiency examination to be publicly listed as proficient; action level pci l is No state-specific action level; follows EPA recommended 4 pCi/L; school testing required is No mandatory requirement; school regulations recommend the use of radon prevention strategies in new construction, recorded from its source on 2026-08-15.
- jurisdiction
- Montana
- disclosure required
- Yes; sellers must provide a disclosure statement regarding adverse material facts including whether the property has been tested or treated for radon. Must also provide a general radon warning statement and disclosure of known radon test results.
- testing mandated
- No mandatory residential testing requirement
- professional certification required
- Yes; radon professionals must pass a U.S. EPA proficiency examination to be publicly listed as proficient.
- action level pci l
- No state-specific action level; follows EPA recommended 4 pCi/L
- school testing required
- No mandatory requirement; school regulations recommend the use of radon prevention strategies in new construction.
- statute citation
- Montana Code §§ 70-20-502, 75-3-601--607, 50-1-206
What the source says
Requires sellers of residential real property to provide purchasers a disclosure statement regarding any adverse material facts that concern the property and of which the seller has actual knowledge. The disclosure statement must include whether the property has been tested or treated for asbestos, radon, lead-based paint, or mold
— eli.org, retrieved 2026-08-15
Source
- eli.orghttps://www.eli.org/sites/default/files/files-pdf/2025%20Radon.pdf