RECOMMENDATIONS (as per ANSI-AARST Radon Measurement in Homes Standard)

Average test result is 4.0 pCi/L or greater: YOUR RADON IS HIGH

• FIX THE BUILDING. Test results indicate occupants may be exposed to radon concentrations that meet or exceed the EPA action level of 4 pCi/L or greater.
• Efforts to reduce radon concentrations are not complete until a retest provides evidence of mitigation effectiveness.
• Complete a short-term test between 24 hours and 30 days after installation of a mitigation system.
• Retest every 2 years to ensure the system remains effective.

Average result is between 2.0 and 4.0 pCi/L: YOUR RADON IS MODERATELY ELEVATED

• CONSIDER FIXING THE BUILDING. Test results indicate radon levels greater than half the EPA action level.
• The World Health Organization (WHO) recommends mitigation if levels are 2.7 pCi/L (100 Bq/m³) or higher.
• Note that tests conducted when the heating system is active both day and night are more likely to provide a clear characterization of potential radon hazards.

Average test result is less than 2.0 pCi/L: YOUR RADON IS LOW

• NO FURTHER ACTION REQUIRED AT THIS TIME. The average indoor radon level is estimated to be about 1.3 pCi/L; the normal outdoor air radon level is 0.4 pCi/L.
• Radon levels in a building can fluctuate due to weather conditions and other factors, including renovations and alterations, or changes in the HVAC system. For this reason, EPA recommends retesting your home every 5 years and remediating if levels become elevated.

• A new addition is constructed or alterations for building reconfiguration or rehabilitation occur.
• A ground contact area not previously tested is occupied, or a home is newly occupied.
• Heating or cooling systems are significantly altered, resulting in changes to air pressure relationships.
• Ventilation is significantly altered by extensive weatherization, changes to mechanical systems or comparable procedures.
• A mitigation system is altered, modified, or repaired.
• Significant openings to soil occur due to:
• Groundwater or slab surface water control systems that are altered or added (e.g., sumps, perimeter drain tile, shower/tub retrofits, etc.).
• Natural settlement causing major cracks to develop.
• Earthquakes, construction blasting, fracking, or formation of sink holes nearby, or
• A mitigation system is altered, modified, or repaired.