New does not mean low. Test after occupancy under normal living conditions. If a passive stack exists, activating it with a fan is often straightforward when results are high.
RRNC and passive systems
Radon-resistant new construction typically includes a layer of gas-permeable material under the slab, plastic sheeting, sealed sumps, and a vertical PVC stack. Without a fan, that stack is passive. Passive systems help some homes and fail to fully control others—measurement decides.
When to test a new home
After you move in and the house operates normally through a representative weather period. Real estate short-term tests still apply if you are purchasing a speculative build.
Activating a rough-in
Many activations add an inline fan and verify performance with a manometer plus air testing. See how mitigation works.
Need a local next step? Call (605) 600-6282 to talk through testing, real estate timing, or mitigation for your Rapid City–area home.