Here’s the headline, folks: Reverse osmosis does NOT remove radon. In fact, it might make things slightly worse if you’re not careful. I know, I know—you just spent your Saturday installing that shiny filter under the sink. But radon is a sneaky little gas molecule, and RO membranes are designed to catch larger stuff like lead, arsenic, and dissolved salts.
Imagine trying to catch a mosquito with a fishing net. That’s your RO filter against radon. The gas slips right through the membrane because it’s not a dissolved solid—it’s a volatile gas. So unless you’ve got a carbon filter or aeration system as a sidekick, that radon is happily taking a ride into your drinking water.
Why Radon Is a Water-Borne Trickster
Radon forms naturally from uranium decay in soil and rock. It can seep into your groundwater, and when you run a shower or flush a toilet, it off-gasses into your air—where you breathe it in. That’s the real danger, not just drinking it (though that’s not great either). Your RO system, bless its heart, is busy removing minerals, but it doesn’t give a hoot about gas.
Side note: If you were hoping for a one-stop-shop solution, sorry—radon is the diva of contaminants. It demands its own special treatment, like granular activated carbon (GAC) filters or aeration tanks. And yes, that means spending more money. Welcome to homeownership, am I right?
