If you're buying a home in Maryland or Northern Virginia, test for radon. Montgomery, Howard, Fairfax, Stafford and Baltimore counties are EPA Zone 1, the highest radon-potential category, and homes anywhere in the region can test high. You can't see or smell it. A professional test takes 48 hours, costs $199 with Polaris, and gives you leverage if the number comes back high.
What radon is and why it matters here
Radon is a radioactive gas that seeps up from soil and rock into basements and crawlspaces. The EPA lists it as the second-leading cause of lung cancer in the US. The DMV's geology makes elevated levels common, especially in homes with basements.
Montgomery County requires a test before most sales
Since October 1, 2016, a single-family home (detached or townhouse) in Montgomery County must be tested for radon before settlement. The test must be done within one year before the settlement date, using a device approved by the county's Department of Environmental Protection. The seller either tests or offers the buyer the chance to test, and both buyer and seller get a copy of the results.
Condos and co-ops are excluded, as are some sales like foreclosures and estate transfers, and homes in the towns of Barnesville, Kensington and Poolesville. The law requires a test, not a fix, so buyers who want high levels addressed should add a radon contingency to the contract. Details are on Montgomery County's radon page.
How a professional test works
- We place a continuous radon monitor in the lowest livable level, usually the basement.
- It records for at least 48 hours with windows and doors kept closed.
- You get a digital report with the average level and what it means.
DIY charcoal kits are cheaper, but they're easy to disturb and slower to return results, and that matters when your contingency clock is running.
If the result is 4.0 pCi/L or higher
That's the EPA's action level. A mitigation system usually costs $1,200–$2,500 and is installed in a day. Most buyers ask the seller to install one or give a credit at closing. A high result is a negotiation point, not usually a reason to walk away.
Book it with your inspection
Radon testing is $199 on its own, or part of our Buyer's Peace of Mind bundle (inspection, radon and termite) at $50 off. Book online or call or text (301) 781-7800.