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Multifamily Radon Testing and Mitigation Requirements

What does it mean to building owners, investors, and property managers?

US Department of Housing and Urban Development (HUD)

In 2013, two years after the Environmental Protection Agency (EPA) released the Federal Radon Action Plan for single family homes, the HUD Office of Multifamily Housing issued a policy that requires Radon testing and mitigation – if testing shows Radon levels are 4 picocuries per liter (4 pCi/L) or higher – for the following multifamily mortgage types:

Housing Act / Mortgage types that now require Radon testing

Section 220

 New construction or substantial rehabilitation of mixed use projects in urban renewal area

Section 221(d)(4)

 New construction or substantial rehabilitation of multifamily rental or cooperative housing for moderate income families, elderly, and the handicapped by profit motivated sponsors

Section 223(f)

 Purchase or refinance of existing multifamily rental housing that does not require substantial repairs

Section 231

 Construction and substantial rehabilitation of rental housing for the elderly or disabled

Section 223(a)(7)

 Refinance of original HUD insured mortgages. Radon testing is not required, but is encouraged.

What does HUD require for multifamily Radon testing?

  • HUD requires submission of a Radon Report with testing results and details of any needed mitigation.
  • HUD requires that all testing and mitigation be performed under the supervision of a certified or state licensed Radon Professional.

What are the accepted standards for Radon testing in multifamily buildings?

Until 2013, there were no guidelines for testing or mitigation of Radon in multifamily buildings. The American Association of Radon Scientists and Technologists (AARST) and the American National Standards Institute (ANSI) published the Protocol for Conducting Radon and Radon Decay Product Measurements in Multifamily Buildings. These published standards are now used by HUD as the required protocol with one exception:

The AARST-ANSI protocol for testing states that 100% of ground floor units must be tested in a multifamily building. However, the exception is that HUD requires “at least 25% of randomly selected
ground level units are to be tested for Radon.”

What are the accepted standards for Radon mitigation in multifamily buildings?

If Radon testing confirms levels of 4 pCi/L or higher, then HUD requires mitigation.The American Society for Testing and Materials (ASTM) has developed 2 Radon mitigation standards, accepted by HUD. ASTM E2121-13 is the standard practice for installing Radon mitigation systems for existing, low-rise residential buildings and ASTM E1465-08a is the standard practice for Radon control options for the design and construction of new, low-rise residential buildings.

What does HUD require from the building owner or investor with regards to multifamily Radon testing?

  1. Comply with testing mandates as dictated by the HUD, state laws, and lender requirements.
  2. Ensure that all testing and mitigation is performed to the stated AARST and ASTM protocols and is performed under the supervision of a certified and/or state licensed Radon Professional.
  3. Notify residents of forthcoming testing as per the ANSI-AARST guidelines.
  4. Notify residents prior to and after any mitigation activities.
  5. Complete and submit a Radon Report certification of completion once Radon testing and/or mitigation are completed.

What are the responsibilities of property managers of multifamily buildings?

  1. Contract with certified and/or state licensed Radon Professional.
  2. Facilitate document and information exchange with the contracted Radon Professional.
  3. Facilitate tenant notification before testing and mitigation including distribution of educational materials with explicit closed-building instructions to ensure an accurate test.
  4. Supervise all unit entries for the Radon Professional.

Are there any HUD Radon requirements for condominiums?

Condominiums that operate as a single owner unit do not fall under the HUD Radon directive. However, a project that was built as condos but is now operating as a rental property would be subject to the policy.

What about Radon requirements for existing privately owned multifamily buildings?

Radon testing and any needed mitigation for privately owned apartment developments are now subject to state and/or local jurisdiction.

  • For example, Maine required Radon testing in all residential rental properties as of March 1, 2014; and unless a mitigation system was installed, a tenant can request a re-test every 10 years. Find out what your state mandates for Radon testing by clicking on this helpful link from the EPA. Check back often, the Radon requirements, especially for multifamily buildings, periodically change.


Other Helpful Links:

The HUD Multifamily Radon Policy information can be found via this link:


Information and Radon standards from AARST can be found via this link:


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