Radon in Apartments and Condos: What Renters and Owners Should Know

Radon and Multi-Unit Housing

Radon risk in apartments and condos is real but floor-dependent. Radon enters buildings the same way it enters houses — through cracks and openings in the foundation and slab — and then concentrates in ground-level and below-grade spaces.

Risk by floor:

• Basement units: Highest risk — often comparable to a single-family home basement
• Ground floor (1st floor): Elevated risk — concrete slab or wood framing sits directly over the soil
• 2nd floor and above: Risk decreases significantly with each floor; radon disperses as it moves through the building
• High-rise apartments above the 5th or 6th floor: Very low risk in nearly all cases

If you live in a ground-floor or basement apartment, particularly in a high-radon state, testing is worthwhile.

How to Test Your Apartment

A short-term radon test kit ($17–$25) works exactly the same in an apartment as in a house. Place the canister in the lowest occupied room of your unit (living room or bedroom — not bathroom or kitchen), leave it for 48–96 hours with windows closed, then mail it to the lab. Results come back in 3–5 days.

You don't need landlord permission to test your own unit's air — the test kit is entirely self-contained and leaves no trace.

Important: Test in your unit, not a common area or basement mechanical room. You want to know what you're breathing in your living space.

If Your Test Comes Back Above 4.0 pCi/L

Step 1: Tell your landlord in writing

Send a written notice (email is fine, certified mail is better) to your landlord documenting the test result. Include a copy of the lab report. This creates a record and triggers any disclosure obligations the landlord may have.

Step 2: Know your state's requirements

Some states have radon disclosure requirements for landlords:

• Illinois, Pennsylvania, New Jersey: Require landlords to disclose known radon issues
• Several states: Require testing in certain circumstances (school buildings, etc.)
• Most states: Have no specific radon requirements — rely on general habitability standards

Check your state's landlord-tenant laws and health department resources.

Step 3: Request mitigation in writing

If your landlord is unresponsive, escalate in writing. A formal written request citing habitability standards and the specific test result puts them on notice. Most landlords in high-radon states are aware of the liability risk and respond to a documented test result.

Step 4: Contact your state radon program

Every state has a radon program through the health or environmental department. They can provide documentation of local risk levels and sometimes mediate landlord-tenant radon disputes.

Step 5: Local housing authority

If your landlord refuses to act, a complaint to the local housing authority under habitability provisions is the next option. The success of this approach varies significantly by jurisdiction.

Condo Owners

If you own a ground-floor or basement condo unit:

• You can test your own unit without HOA permission
• Mitigation for your unit specifically may require HOA approval depending on the work involved (exterior penetrations, common area access)
• Request a building-wide assessment through your HOA board if your test comes back elevated — neighboring units likely have similar levels
• Full building mitigation (one system serving multiple units through shared sub-slab space) is often more cost-effective than individual unit systems

The Practical Reality for Renters

In high-radon states with no landlord requirements, renters have limited legal leverage if a landlord refuses to act. Practical options when negotiation fails:

• Request a lease modification: Ask for a rent reduction to reflect the habitability concern, documented in the lease addendum
• Move: In states without radon requirements, this is sometimes the only practical remedy — particularly for month-to-month tenants
• Buy an HRV: A heat recovery ventilator ($700–$1,500 installed, requires landlord permission for installation) can reduce levels by 25–50% through dilution — not as effective as mitigation but meaningful

The most common positive outcome is landlord-paid mitigation after receiving a written test result. Most landlords, once presented with a documented health hazard in their property, choose to act — the liability exposure of inaction is clear.

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