How to Know if a Radon Mitigation System is Working

When uranium and thorium naturally decay, they produce a radioactive gas. Air that contains radon can be detected by a radon mitigation system. This system will remove the air containing radon from its source underneath the building. The system should be tested periodically to assure that it is properly functioning and correctly assessing the air.

Radon mitigation systems reduce the potential of health hazards cause by decaying uranium and thorium gases. These systems work by sucking radon-laden air out of the spaces underneath a building. Radon gas concentrations are usually measured in picocuries per liter (pCi/L).

The steps to follow for checking a radon mitigation system are:

1. Ensure that the system's fans are turned on and it is plugged in, i.e. set to a normal functional state.


2. Locate the manufacturer's performance specifications of the system. Take note of the expected or guaranteed performance numbers.


3. Check the system's vacuum monitor. Usually there is an indicator device that uses columns of a colored liquid inside a curved tube. There is a problem with the air pressure if the two columns in the tube are at or near the same height. The air intake is properly functioning if the heights of the two columns are well-separated.


4. Confirm the airflow intake. Often there are small holes in the basement floor, referred to as check ports, that are to be used to check the air flow. Hold a lit cigarette or smoke pencil next to a hole, watching the direction of the smoke. The system intake is working properly if the smoke is sucked into the hold. If this does not occur, it indicates that there is a problem with the sub-floor ventilation.


5. Check the exhaust functioning. Determine whether or not air is being blown out of the vents. Problems with the motor, fan or piping are indicated by poor airflow.


6. Take a radon measurement. To do this accurately, use a test kit that is EPA certified, or contact a professional tester. If you use a kit, follow the instructions that accompany it. When the testing is completed the kit should be returned to the lab for processing. The results will be sent to you when they are available.

If there are any issues or concerns about the radon mitigation system functionality, contact the installer or a radon professional. They will work with you to establish a less hazardous radon level.