What is the major source of radiation in our homes?

Radon is the major source of radiation in most homes. It is a radioactive gas you cannot see, smell, or taste, and the EPA names it the largest source of radiation exposure for most people. It seeps up from the ground into your basement and lower floors, and over years of breathing it, it raises your risk of lung cancer.

Here is what is happening under your house. Uranium in the soil and rock breaks down naturally. As it breaks down, it gives off radon gas. That gas moves up through the dirt and finds the easiest way in: cracks in the slab, the floor wall joint, gaps around pipes, a dirt or fieldstone crawl space. New Hampshire and Maine sit on a lot of granite, and granite is one of the rock types that gives off more radon. So this is a common problem up here.

The radiation part trips people up. The gas itself is not the whole story. As radon decays it makes tiny radioactive particles. You breathe those in. They lodge in your lungs and keep giving off small bursts of radiation right against the tissue. That is the part that does the damage over time.

How much radon is too much

The EPA sets the action level at 4.0 pCi/L. At that number or above, you should fix it. Between 2 and 4 pCi/L, the EPA says consider fixing it. There is no level that is officially “safe,” but those are the marks the EPA uses, and they are what we go by in the field.

You will not know your number without a test. A nose does not detect radon. A neighbor’s reading does not tell you yours, because two houses on the same street can read very differently. So you test. Our radon test fee is $50, credited toward the job if you move ahead.

How you fix it

If your test comes back high, the fix is a radon mitigation system. For a normal basement with a poured or block slab, that is an active sub-slab system: we pull the gas from under the floor and vent it up and out above the roofline before it ever gets into the house air. For a dirt or fieldstone crawl space, the fix is sub-membrane depressurization, where we seal a barrier over the dirt and pull the gas out from under it. We install both kinds. Our radon guy Branden runs that side of the house, and yes, the crew calls him B-Radon.

Radon mitigation cost is $900 to $6,000, and most homes land around $1,950 to $2,250. The system carries a 10-year warranty. That warranty covers the system, not a guaranteed radon number, unless we put a number in writing. Radon levels move with the seasons and with how the house is run, so we do not guarantee a reading by default.

A teach-don’t-sell note. You do not need a mitigation system until a test says you do. If your house has never been tested, the first and cheapest step is a test, not a system. Test first. If your number is under 2 pCi/L, you are fine and you do not need us for radon yet.

Now, radon and water often travel together. The same cracks and the same floor wall joint that let radon in also let water in. The reason water pools at your foundation in the first place is the backfill: when the house was built, the soil dug out for the hole got loosely put back, and that disturbed fill drains slowly and holds water against the wall. NH frost heave then pushes on those walls. If you are dealing with a wet basement on top of radon, our basement waterproofing page covers the drainage fix, and a dirt crawl usually needs crawl space encapsulation anyway, which pairs cleanly with a sub-membrane radon system.

We are 603 Basement Solutions, out of East Kingston NH, and we serve New Hampshire, Maine, and Massachusetts. We are state radon certified (RMS-113966), licensed and insured. Trusted by 5,000+ homeowners in New England, 4.9 on Google across 250 reviews, BBB A+ accredited.

Want to know your number and what a fix would run? Call us at 603-610-1770 or book your free inspection. Free inspection, free estimate, quote back within 24 hours. See what stands behind the work on the 603 guarantee page.

Related questions

Is radon worse in New Hampshire basements? It is common here. NH sits on granite, which tends to give off more radon, and basements are the entry point. The only way to know your house is to test. See radon mitigation.

Can I smell or see radon? No. Radon has no color, no smell, no taste. That is why the EPA pushes testing. A test is the only way to find it.

Does a radon system also keep my basement dry? No. A radon system handles gas, not water. They share the same entry points, so people fix both, but for water you want interior drainage. See basement waterproofing.

Do I need to retest after you install the system? Retesting is the homeowner’s call and the homeowner’s job. We install the system to pull radon out. If you want to confirm your number later, you run another test.