Radon FAQ for Rapid City homeowners
Short answers to the questions we hear most—then deeper guides when you want the full story.
Is Rapid City a high radon area?
Yes. Pennington County is in EPA Radon Zone 1, the highest predicted indoor potential. Individual homes still vary—only a test measures your address.
What radon level requires mitigation?
EPA recommends fixing homes at or above 4.0 pCi/L. Consider mitigation between 2 and 4 pCi/L, especially for basements you use often.
How long does radon testing take?
Short-term professional continuous monitors often run about 48 hours. Long-term alpha-track tests run 91+ days for a better annual average.
Can I do a DIY kit instead?
Yes for screening if you follow placement and closed-house rules carefully. Use professional testing for real estate and high-stakes decisions.
Does mitigation work?
Active soil depressurization reliably lowers indoor radon in most homes when designed and installed correctly and then verified with a post-mitigation test.
How much does mitigation cost?
Many systems fall roughly in the $800–$2,500 national planning band; complex foundations cost more. Call for a property-specific discussion.
Do new homes need testing?
Yes. New, tight construction can still trap radon. Passive rough-ins help but do not replace a post-occupancy test.
How often should I retest?
About every two years, after mitigation, after finishing a basement, and when buying or selling.
Is radon only in basements?
Levels are usually highest in the lowest level, but upper floors can also be elevated. Test the lowest regularly used level.
Who should I call?
Call Rapid City SD Radon at (605) 600-6282 for testing, results questions, and mitigation help in the Rapid City area.
Still stuck on a number or a contract deadline? Call (605) 600-6282.