MONTGOMERY COUNTY, MARYLAND

Radon testing requirements for sales and rentals.

Clear, practical guidance for homeowners, real estate professionals, landlords, and property managers.

VIEW THE REQUIREMENTS

Local rules. A straightforward path to compliance.

Montgomery County has distinct radon-testing rules for the sale of covered homes and for ground-contact or basement rental units. The requirements differ by transaction, but both are intended to ensure that occupants receive current results.

Professional testing for a local requirement.

Envirolabs serves leading property management companies, housing agencies, real-estate professionals, and individual owners throughout Montgomery County. For portfolios and larger projects, contact us to discuss corporate rates and project quotes.

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TWO REQUIREMENTS — ONE LOCAL RESOURCE

Know which rule applies to your property.

This page summarizes County requirements. It is informational and should be used with the applicable County Code and your professional advice.

01 / HOME SALES

Before settlement

For a single-family home or townhome located in Montgomery County:

  • A radon test must be performed less than one year before settlement.
  • The seller must test or permit the buyer to test.
  • Both seller and buyer must receive the results.

County Code §40-13C

02 / RENTAL HOUSING

Before leasing

For ground-contact or basement units in covered single-family and multifamily rentals:

  • Test results must be within three years before the lease date.
  • At signing, tenants receive results below 4.0 pCi/L and radon education.
  • Confirmed elevated results require follow-up and mitigation steps.

County Code §29-35E / Bill 26-22

FOR PROPERTY MANAGERS

Build radon testing into your turnover plan.

01Review portfolio

Identify covered ground-contact and basement units.

02Schedule testing

Coordinate access and closed-building conditions.

03Receive reports

Keep current, unit-specific results ready for lease files.

04Plan ahead

Ask Envirolabs about portfolio pricing and larger projects.

Important: Covered rental units with results at or above the EPA action level of 4.0 pCi/L have additional County follow-up, disclosure, and mitigation requirements. See County Code §29-35E for complete terms and exceptions. Properties within the City of Rockville may be subject to separate local rules.