Radon Testing Procedures

So far we’ve learned a bit about what radon is and why it’s a good idea to test your home for elevated radon levels. Now we’ll take a look to see what the testing procedures are.

Radon levels change from hour to hour, so I want to first eliminate a common misconception: a home does not have a specific radon level. It is not as if your home, once tested, will remain at that same level if tested later. During our testing we get readings every hour, and the readings show trends and movements, which is why it is very important to take radon levels according to EPA testing protocol to get a good idea of the overall radon level.

In reality, the longer the test, the better. We’re talking about months here, not weeks or days. Since radon levels fluctuate, the longer the test during normal operating conditions, the better idea you will get of the potential health concerns you may have with radon levels within your home.

That is all well and good for existing homeowners, but what about a real estate transaction in which the buyer does not have weeks or months to have a test performed? Fortunately, a protocol exists to help give as accurate a picture as possible in a pretty limited time.

EPA testing protocol requires a test last a minimum of 48 hours. It must be carried out on the lowest livable portion of the home (for example, even an unfinished basement, since it could be finished in the future) under “closed house” conditions. This last part can be tricky. Closed house conditions mean the doors and windows must be closed for the duration of the test except for normal coming and going.

I’m afraid to say we have encountered unscrupulous sellers in the past who have tried to trick the system by venting their home. They open up a few windows to help the home “breathe” a little better despite our notifications that such actions invalidate the test. Our testing equipment is pretty sensitive, and we can identify if the machine has been moved, if the barometric pressure changes, if the temperature changes- all indicators that the test may have been tampered with. The few cases in which we see the windows open generally do not go well since the seller inserts a level of distrust into the process by their actions. Of course we retest since those results would be invalid.

Most home inspectors in Southern Indiana use a continuous radon monitor (CRM) that is essentially a box filled with electronics. Some still use charcoal canisters, but these have the disadvantage of lacking tamper-proof indicators, and it is nearly impossible to know a charcoal canister test is valid without observing the home’s conditions throughout the test.

All this radon discussion may be a little confusing, but hang in there! The good news is next time, but I’ll give you the punchline now- radon is really easy to mitigate. We’ll talk about how it’s done and a little bit about the science behind the fix.