A Boulder County radon-resistant new home still needs a test

Seeing “radon-resistant construction” on a new Boulder County home is good news, but it is not the finish line.

New single-family homes must be built with radon-resistant construction in several local jurisdictions here, including unincorporated Boulder County. That requirement gets a passive system into the house from day one. Even so, a home built this way should be tested as soon as possible after move-in to confirm the system is actually lowering radon levels. If the test comes back elevated, a fan can be added to make the system active, and then the house should be retested to be sure the fix worked.

The reason the test still matters is simple: radon is invisible, and it is prevalent across this area. A buyer can easily read “radon-resistant” and assume the air is fine without anyone ever measuring it. The honest version is two steps, not one. Build with a system, then test the actual house you are living in, because only the test tells you what is in your air.

Keep the result with the home file, especially if a fan or full mitigation system gets added later, so the next reading has something to compare against. Boulder County Public Health’s radon pages walk through testing and the resistant-construction requirement if you want the details.