Testing and radon levels
What to Do After a High Radon Test in Billings
Keep the full report, match the next step to the test and timeline, then gather enough building detail for a qualified mitigation proposal.
Illustration for explanation only. It is not a photograph of our work.
Start with the report, not the fear
A result at or above 4 pCi/L reaches the level where EPA recommends fixing the home. EPA also says people may consider fixing between 2 and 4 pCi/L because no known safe exposure level exists. Those statements guide a decision, but the first practical task is to understand how the measurement was produced.
Save the complete report. Record the device or laboratory, start and stop times, room, floor, test duration, units, and any unusual conditions. A cropped display photo may omit the information a measurement professional or mitigator needs.
Radon Reading Next-Step Tool
Put your reading in context
Enter the number from your report. The response follows current EPA action-level guidance.
Educational guidance only. This tool does not diagnose health risk, validate a test, or design a mitigation system.
Use the units printed on the report. This tool expects picocuries per liter.
Check whether the test fits the decision
A short-term screening test, a professional real-estate test, a long-term test, and a continuous monitor can answer related but different questions. The right follow-up depends on the first result, test quality, time available, and whether a signed transaction controls the deadline.
If a device may have been moved, windows were left open contrary to the protocol, the monitor was placed in a poor location, or severe conditions affected the test, do not guess. Ask a qualified measurement professional what the applicable standard requires.
Do not use the county map as a verdict
EPA’s county zone map was built for broad planning and code-related purposes. EPA explicitly says it should not determine whether an individual home needs testing. Homes with elevated results can occur in any zone, and neighboring homes can measure differently.
The Billings address, neighborhood, home age, or foundation type cannot replace a test. Area data can provide context, but it does not predict one property’s result.
Prepare for mitigation estimates
A qualified mitigator needs more than the number. Share the report and provide access to the lowest level, sump, crawlspace, mechanical room, garage, exterior walls, and likely pipe routes. Point out additions, finished walls, past foundation work, and future remodeling plans.
Ask each provider to explain the assumed foundation zones, suction approach, pipe and fan route, electrical responsibility, sealing scope, system monitor, documentation, and post-mitigation test. Compare written scopes instead of comparing a total with no design basis.
Verify the result after installation
A running fan and a changed manometer show that the system is creating pressure, not what the indoor radon concentration is. A radon test verifies initial effectiveness. EPA consumer guidance says the post-mitigation test should occur within 30 days, but not sooner than 24 hours after the system begins operating.
Keep the before and after reports, proposal, invoice, system description, labels, operating instructions, and written installer warranty. Check the system warning device regularly and retest periodically.