Radon Testing in Apartments and Condos: What Tenants Need to Know

Radon is commonly associated with single-family homes, but apartment and condominium residents face meaningful radon exposure risk — particularly in garden-level and first-floor units. The key differences from homeowner situations: tenants typically cannot install mitigation systems themselves, disclosure requirements vary significantly by state, and the responsibility for testing and remediation rests with the property owner or landlord.

Which Apartment Units Are at Risk

Radon enters buildings from the soil through the foundation — the same mechanism as in single-family homes. In multistory apartment buildings and condominiums:

• Garden-level and below-grade units: Highest risk. Units partially or fully below grade are in direct contact with the soil and foundation, similar to a basement in a single-family home.
• First-floor units: Elevated risk compared to upper floors. Radon entering the building from the foundation may concentrate on the lowest floors before dispersing upward.
• Upper-floor units (2nd floor and above): Lower risk. Radon entering the basement or first floor is diluted by building air exchange before reaching upper levels. However, radon can still accumulate in poorly ventilated upper-floor units in some building types.
• Slab-on-grade construction (no basement): First floor units in slab construction may have direct soil-contact risk similar to a single-family slab home.

Testing in Rental Units

Tenants can conduct their own radon tests in their rental unit using standard DIY charcoal canisters — the same devices used in single-family homes. Placement protocol is identical: lowest floor of your unit (for most tenants this is the main living level), breathing zone, away from HVAC vents and windows.

Before testing, check your lease: some leases restrict modifications or installations without landlord consent. A charcoal canister placed on a shelf does not constitute a modification — but a continuous electronic monitor plugged into an outlet may warrant a conversation with the landlord first in some jurisdictions.

Landlord Obligations: State-by-State

Federal law does not mandate radon testing or disclosure in rental properties. State requirements vary substantially:

• States with landlord radon testing or disclosure requirements: Illinois requires radon disclosure in certain circumstances; Maine has radon disclosure requirements for property transfers; other states have specific requirements for subsidized housing or federally assisted properties. Requirements change — check your state health department’s current radon program guidance.
• HUD and federally assisted housing: The Department of Housing and Urban Development (HUD) has established radon testing and mitigation requirements for federally assisted multifamily housing in high-radon zones. Tenants in HUD-assisted housing in EPA Radon Zone 1 states have specific protections.
• Implied habitability: In states without specific radon laws, elevated radon may qualify as a habitability issue under general landlord-tenant law — particularly if the landlord has been notified of elevated levels and refuses to address them. This is a developing area of law that varies by jurisdiction.

What to Do If Your Test Shows Elevated Radon

• Document the result: Keep the lab report, note the test dates, device placement location, and conditions during the test
• Notify your landlord in writing: Send written notice (email with read receipt, or certified mail) providing the test result and requesting remediation. Keep a copy of all correspondence.
• Reference your state’s requirements: Include any applicable state radon disclosure or habitability statute in your request
• Contact your state radon program: Most states have a radon program (through the health or environment department) that provides guidance to tenants and can sometimes mediate landlord disputes
• Consult a tenant’s rights organization or attorney: In states where elevated radon may implicate habitability, a brief legal consultation clarifies your options

Mitigation Options for Renters

Tenants generally cannot install permanent radon mitigation systems without landlord consent — installing a core hole through the concrete slab and running pipe through walls requires property owner authorization and typically a building permit. However, some options exist:

• Request landlord-installed mitigation: The most appropriate path — and the landlord’s obligation in states with relevant statutes or under implied habitability doctrine
• HEPA air purifiers with activated carbon: Some reduction in radon decay product attachment to airborne particles, reducing the fraction that deposits in lung tissue. Not a substitute for source control but can provide modest supplemental reduction in a unit where mitigation is delayed.
• Increased ventilation: Opening windows when weather permits reduces radon concentration through dilution. Not a permanent solution but may reduce short-term exposure while advocacy with the landlord proceeds.
• Relocation: In severe cases with unresponsive landlords and no legal remedy, relocating to a non-ground-floor unit or a different property may be the practical solution

Frequently Asked Questions

Is radon a problem in high-rise apartments?

Above the second floor, radon risk diminishes substantially in most building types. High-rise apartments on upper floors rarely have elevated radon because soil gas entering the building at the foundation is diluted by the building’s air volume before reaching upper floors. Ground-floor and below-grade units are the primary concern in multifamily buildings.

Can I make my landlord fix a radon problem?

It depends on your state. In states with specific radon statutes, landlords have defined obligations. In other states, the implied warranty of habitability may apply — elevated radon that poses a health risk could constitute a habitability defect, particularly if the landlord has been notified and refuses to act. A tenant’s rights attorney in your state can advise on specific remedies available.

My apartment is on the third floor — should I still test for radon?

Third-floor radon is uncommon but not impossible, particularly in older multifamily buildings with poor air exchange, poorly ventilated common areas, or building materials (concrete, granite) that emit radon directly. Testing is inexpensive and provides certainty. If your third-floor result is elevated, it is unusual enough to warrant a second test before assuming it is accurate — and a conversation with building management about whether lower floors have been tested.