New Radon Standards for Multifamily Housing

Changes in effect June 30, 2023


If you build, own, manage or live in multifamily housing property, you should be aware of changes to radon standards on the horizon. Specifically, these are upcoming changes to the Federal Housing Finance Agency’s Fannie Mae and Freddie Mac standards for sellers and servicers regarding multifamily housing properties. Certified Radon has compiled a few highlights on the new radon standards going into effect for loan applications after June 30, 2023:

  • Radon testing will be required at multifamily properties backed either Fannie Mae or Freddie Mac, regardless of property location.
  • 100% of ground contact units (including basement(s), when applicable) and 10% of units on additional floors will require testing. (Note that Certified Radon will also conduct duplicates in 10% of selected areas and field blanks in 5% of selected units on our partner projects.)
  • Environmental professionals and/or property reps are required to notify tenants of radon testing.
  • Additional guidance on radon standards and compliance with local/state radon laws will be provided to lenders and environmental consultants. 


While radon testing standards are expanding to better protect multifamily properties, there are some exceptions and/or deferrals for loans that will not be subject to radon testing, including refinancing properties with current Fannie Mae or Freddie Mac balances that have been previously tested and/or mitigated per their policies, supplemental loans, cooperatives, manufactured housing areas, residential properties with no ground contact, upper floor units, new construction with radon resistant features, properties with existing radon mitigation systems and Operations & Maintenance programs, and small loan/Small Balance Loan (SBL) mortgages. 


The new standards can be complex. In addition to working with a qualified, reliable radon testing consultant, such as Certified Radon, property owners, managers and lenders should consult federal, state and local regulatory agencies, as well as the National Consortium on Radon Standards through ANSI/AARST to ensure their actions are aligning with the new standards and meeting requirements


To learn more about Certified Radon and our Commercial and Multifamily radon testing and mitigation services, call 816.587.3500 or visit