Guides

Radon guides

What radon is, how to test, what the numbers mean, and how homes are fixed. Written from EPA, CDC, and state health-department sources.

Radon basics

Radon is a radioactive gas from uranium in soil and rock. Here is where it comes from, how it enters a house, and why levels vary so much.

Why EPA ranks radon as the second leading cause of lung cancer, how smoking multiplies the risk, and what the numbers do and do not mean.

How radon gets into private well water, why the main risk is breathing it after it escapes indoors, and how to test and treat.

What EPA's 1993 Map of Radon Zones measures, how the three zones were set, its limits, and how to use it well.

Common misconceptions about radon, from 'only old houses' to granite countertops, checked against EPA guidance.

Where to put a test kit, how long to leave it, closed-house conditions, and how to avoid the mistakes that spoil results.

How short-term and long-term radon tests differ, which devices are used, and how to combine them before deciding on a fix.

Sub-slab depressurization and other radon reduction methods explained, what installation involves, and how to check a system is working.

The basic features of radon-resistant new construction, why they cost less during building, and how to activate the system if needed.

How radon testing fits into a home sale, which test options give fast results, and what buyers and sellers should ask.

Whether renters should test for radon, which apartments are most at risk, how to raise it with a landlord, and where state rules apply.