Understanding Montgomery County Bill 26-22

07/31/2023 1:47 PM | Lorin Stieff (Administrator)

Understanding Montgomery County Bill 26-22

Bill 26-22 became effective on July 1, 2023. This Bill mandates radon testing (and mitigation, if necessary) in single- and multi-family rental dwellings. Montgomery County is no stranger to radon legislation, and previously enacted Bill 31-15 several years ago, which requires radon testing for single-family home sales.

Bill 26-22 (July 2023)

  • Requires landlords (of both single- and multi-family dwellings) to conduct radon testing in all ground-contact units before lease.
  • Requires landlord to disclose test results to tenants.
  • Requires landlord to mitigate the dwelling if the radon concentration meets or exceeds the EPA action level (4.0 pCi/L).
  • Allows tenant to terminate a lease agreement if the landlord does not adhere to mitigation requirements.

Bill 31-15 (October 2016)

  • Requires radon testing for single-family home sales.
  • Test must have been conducted within a year of the home’s sale.
  • Test results must be provided to both the seller and the buyer.
When did Bill 26-22 become effective?

After a six-month extension, Bill 26-22 became effective on July 1, 2023. The Montgomery Housing Partnership, GCAAR (Greater Capital Area Association of REALTORS®), and AOBA (Apartment & Office Building Association) had originally requested additional delays, but the Montgomery County Council decided that July 1 would provide sufficient time to prepare.

Who will be affected by these changes?

Those most impacted by Bill 26-22 are landlords in Montgomery County, and tenants who are living in properties with elevated radon concentrations. Bill 26-22 provides protection to the public by requiring landlords to mitigate properties with radon levels at or above 4.0 pCi/L.

What are the rules on retesting?

Test results must be within three years before the date of the lease (this is reduced to two years in Rockville, by Ordinance 06-23). As the majority of leases are shorter than three years, this ensures periodic retesting.

What is the jurisdiction of this legislation?

In principle, Bill 26-22 is effective throughout all of Montgomery County. However, each incorporated municipality in the county must “opt-in” to Chapter 29 (Landlord-Tenant Relations) of the Montgomery County Code or pass an Ordinance adopting it, in order to be affected by this regulation. To the best of our knowledge, landlords in the incorporated municipalities of Friendship Heights, Garrett Park, Kensington, Poolesville, and Rockville fall under the jurisdiction of this regulation.

How does Montgomery County Code interact with ordinances passed by incorporated municipalities?

This is a neat question that deserves a bit of a preface. In the United States, federal law (including the U.S. Constitution, federal statutes, and regulations) generally supersedes state law – it is “the supreme law of the land.” And state law (including state constitutions, state statutes, etc.) supersedes county law. It’s therefore interesting to note, per Section 1-203 of the Montgomery County Code, county law does not automatically supersede municipality law. Incorporated municipalities are exempt from county legislation unless they choose to accept it. The intent of this is to foster the practice of “municipal home rule.”

TL;DR Unless they opt-in, incorporated municipalities (such as Rockville, Gaithersburg, etc.) are exempt from Montgomery County legislation.

Do the radon tests need to be conducted by a certified professional?

With the sole exception of post-mitigation radon testing, it does not appear that Bill 26-22 specifically requires that testing or mitigation be conducted by certified professionals.

Does the landlord need to disclose results?

Yep! If results meet or exceed the action level, the landlord must disclose results to each tenant in the dwelling.






The Maryland Chapter's parent organization, Indoor Environments Association, formerly the American Association of Radon Scientists and Technologists is a 501(c) (6) non-profit organization.

*Please note any donations made are not tax deductible for federal tax purposes.

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