Radon in rentals and apartments

Radon does not care whether you own or rent. Renters breathe the same air, and a rental house or ground-floor apartment can have elevated levels.

Which rentals are most at risk

Radon enters from the ground, so the highest levels are usually on the lowest floors. Rented single-family houses, townhouses, basement apartments, and ground-floor units are the most likely to have elevated radon. Upper-floor apartments in tall buildings generally have lower levels, although radon can travel through shafts and shared spaces in some buildings.

Can renters test?

Yes. A short-term test kit is small, inexpensive, and does not require any changes to the unit. Follow the usual placement rules in how to test your home: lowest lived-in level, not in a kitchen or bathroom, at least 20 inches above the floor, with windows closed for short tests. Some state radon programs offer free or discounted kits; see our state pages.

If the result is high

EPA recommends fixing homes at 4 pCi/L or higher and considering a fix between 2 and 4. In a rental, a mitigation system is a building alteration, so it is the owner’s decision and cost unless local law says otherwise.

A practical approach:

1. Do a follow-up test as EPA recommends, so you have two results. The follow-up planner explains the steps.
2. Write to your landlord with the results, the dates, and EPA’s guidance. Keep it factual.
3. Ask whether the building has been tested before and whether the owner will arrange professional testing or mitigation.
4. Contact your state radon program for information on any state or local requirements. A few states and cities have rules about radon disclosure or testing in rental housing; many do not.

Landlord perspective

For property owners, testing and fixing radon is usually a one-time project that protects tenants and can reduce liability concerns. A working mitigation system and recent low test results are useful records to keep.

Public and assisted housing

Some federal housing programs have radon testing requirements for certain properties. If you live in public or assisted housing, ask the property manager whether the building has been tested.

Bottom line

Test if you live on a low floor or in a house, share results in writing, and use your state radon program for local rules and help.

The numbers behind the concern

EPA estimates radon causes about 21,000 lung cancer deaths each year in the United States, including about 2,900 among people who have never smoked. The national average indoor radon level is about 1.3 pCi/L, while the average outdoor level is about 0.4 pCi/L. EPA recommends fixing homes at or above 4 pCi/L and considering fixes between 2 and 4 pCi/L. Renters face the same exposure as owners. The difference is they don't control the building.

To put risk in perspective, EPA's risk tables estimate that if 1,000 people who never smoked were exposed to 4 pCi/L over a lifetime, about 7 could get lung cancer. Among 1,000 smokers at the same level, about 62 could. Smoking multiplies radon risk, which matters in shared buildings too.

Which units in a building test highest?

Radon enters from the soil, so ground-floor and basement units are most likely to have elevated levels. Upper floors are often lower, but not always. Elevator shafts, stairwells, utility chases, and HVAC systems can carry soil gas upward. In garden-level apartments, test in the main living area or bedroom, not in a closet or bathroom.

How to test as a renter

• Buy a short-term test kit from a hardware store, your state radon program, or an online lab. Many states offer low-cost or free kits.
• Follow the instructions exactly, including closed-house conditions for short-term tests: windows and outside doors closed, except for normal entry and exit, for 12 hours before and during the test.
• Place the kit 20 inches or more above the floor, away from drafts, exterior walls, and heat sources.
• Mail it promptly to the lab.
• If the result is at or above 4 pCi/L, run a second test to confirm, either another short-term test or a long-term test.

Some leases restrict changes to the unit, but placing a small test device generally doesn't count as an alteration. If in doubt, tell the landlord you're testing.

Talking to your landlord

If your results are high, share them in writing with the dates, test type, lab report, and EPA's action level. Ask:

• whether the building has been tested before, and what the results were;
• whether the landlord will arrange professional testing of the unit and building;
• whether mitigation will be installed, and on what timeline.

Mitigation in multifamily buildings can be more complex than in single-family homes and may need a professional who handles larger buildings. Your state radon office can explain any landlord radon laws that apply where you live. A few states require radon disclosure or testing in rentals, and some cities have their own rules.

If the landlord won't act

• Check state law. Some states require landlords to disclose known radon levels, or to mitigate.
• Contact your state radon program for guidance on tenant rights.
• Consider local housing or code enforcement offices, if your area treats radon as a habitability issue.
• Reduce your own exposure. Spend less time in the lowest level, improve ventilation where you safely can, and don't smoke indoors.
• Factor it into your next move. Ask about radon testing before signing your next lease.

For landlords

Testing is inexpensive, and mitigation typically costs about as much as other common home repairs, according to EPA. Testing ground-contact units, disclosing results, and fixing high levels protects tenants, reduces liability, and can be a selling point for safety-conscious renters.

Keep copies of all test results and correspondence. If you move, a record of the readings can help the next tenant, and it may matter if a dispute arises.

Renters can protect themselves by testing early, sharing results in writing, and knowing their state's rules.