Homeowner radon guide
Radon in Water: What Homeowners Should Know
For most homes, soil gas is the main source. Radon can also be present in groundwater, especially private wells, and some may move into indoor air when water is used.
Start with indoor air
Test indoor air first. If the home uses a private well and the air result is elevated—or state guidance recommends water testing—follow the state program's sampling guidance.
Testing and treatment
Water sampling is sensitive to collection technique. Where treatment is appropriate, aeration or granular activated carbon may be considered by an experienced professional.
No universal homeowner threshold
Do not rely on a single nationwide number as a universal safe threshold for radon in water. Follow current federal and state guidance.
What to do next
Use the cost estimator for planning or search for professionals whose recorded service area matches your ZIP code.
Content reviewed 2026-08-20. Educational information only; testing and a property-specific assessment are still required.