Guides

• How RadonZoneCheck Reports Your County's Radon Zone — The exact EPA and Census sources behind every county's radon zone rating and national rank, named and sourced.
• What Your County's Radon Zone Actually Means (and Doesn't) — Why EPA says to test every home regardless of its county's zone, and what a Zone 1, 2 or 3 rating can and can't tell you.
• What Radon Testing and Mitigation Actually Cost — Sourced 2026 cost ranges for radon test kits and mitigation systems, and why cost depends on the house, not the county.
• The US Counties EPA's Radon Map Can't Rate Directly — EPA's Map of Radon Zones predates several real county boundary changes. Here is exactly which counties that affects, and why.
• Embed the RadonZoneCheck Radon Zone Badge — A free, live radon-zone badge for any of the 3144 counties this site covers — one iframe, no sign-up, credited back to RadonZoneCheck.