Based on the ANSI/AARST MAH 2019
If your test result is 4.0 pCi/L or greater:
- You should fix the building if test results indicate occupants may be exposed to radon concentrations that meet or exceed the EPA action level of 4.0 pCi/L. Find a licensed mitigator at Radalink.com/mitigators
- Efforts to reduce radon concentrations are not complete until a retest provides evidence of effectiveness. Complete a short-term radon test between 24 hours and 30 days after the installation of a mitigation system.
- You should retest the property every 2 years to ensure the system remains effective.
If your test result is between 2.0 and 4.0 pCi/L:
- Consider fixing the building if the test results indicate radon levels greater than half the action level. Find a licensed mitigator at Radalink.com/mitigators
- Remember that tests conducted when heating systems are active both day and night are more likely to provide a clear characterization of potential radon hazards.
You should retest the property:
- Every 5 years if a mitigation system IS NOT installed
- Every 2 years if a mitigation system IS installed.
- After a mitigation system is altered, modified, or repaired.
- In conjunction with the sale of a new or existing building.
- When any of the following circumstances occur:
- A new addition is constructed or the building is altered for rehabilitation or reconfiguration.
- A ground contact area not previously tested is occupied, or a home is newly occupied.
- Heating and cooling systems are significantly altered.
- Ventilation is significantly altered by extensive weatherization, changes to mechanical systems, or comparable procedures.
- Significant openings to the soil occur because of ground water or slab surface water control systems that are altered or added (ex. sumps, perimeter drain tile, shower/tub retrofits), natural settlement causes major cracks to develop, or when earthquakes, construction blasting, or formation of sink holes occur nearby.
For more information, please see our frequently asked questions page or call us at 1-800-295-4655 during business hours.