Multi-unit guide · source-linked
How to Test an Apartment for Radon
Choose the correct level and room for a radon test inside an apartment, condominium, or other multi-unit home.
Direct answer
In a multi-unit building, CDC says to place the device on the lowest level within your unit. Use a regularly occupied room, follow the device instructions, and do not move the test to a shared basement that is outside the occupied unit.
Reviewed September 5, 2026. United States federal guidance. Device instructions and applicable state requirements take precedence.
Evidence standard
Built from the official primary guidance linked on this page.
Source check
Reviewed September 5, 2026 · maintained by RadonVerdict.
Start with the space you actually occupy
The relevant placement is inside the apartment or condominium unit. CDC's public guidance says residents of multi-unit buildings should use the lowest level within their unit.
A building basement, utility room, or parking level can answer a different property-management question but does not substitute for the occupied unit measurement.
Choose a normal occupied room
Use a bedroom, living room, den, office, or other room where people spend time. Avoid kitchens, bathrooms, closets, high humidity, drafts, heat, and areas where the device will be disturbed.
Follow the exact height and clearance instructions for the chosen device. Record the floor number and room so the result can be understood later.
Coordinate access without changing the protocol
A renter can ask the landlord or property manager about prior testing, building policies, and state resources. Do not allow maintenance work or an inspection visit to move the active device without documentation.
Testing and disclosure requirements vary by jurisdiction and building program. Federal placement guidance does not create a universal landlord duty.
One unit result does not map the entire building
Radon levels can differ between units, floors, and foundation-contact areas. A neighbor's result cannot prove the level in your unit, and your result does not characterize every apartment.
If a building-wide decision is needed, property management should use the applicable multi-family measurement standard or qualified provider rather than extrapolate from one device.
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Open the full test plannerCommon questions
Quick answers
Should I test a high-rise apartment?
Testing decisions depend on location and program guidance, but a test is the only way to measure your unit. Contact the state radon program for local recommendations.
Can I use the building basement result?
It does not replace a measurement inside your unit. The basement can be part of a separate building assessment.
Does my neighbor's low result mean my apartment is low?
No. Radon can vary between nearby spaces, so each result should be tied to its exact location and conditions.
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