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Radon Mitigation System User Guide

A Guide to Your Radon System

SWAT Environmental is the nation’s largest provider of radon mitigation and remediation services. Our business has grown since it was first established in 1988 due in part by our early participation in the EPA Radon Contractor Proficiency Program. We believe it is our responsibility to create healthier homes and workplaces in neighborhoods everywhere. This commitment will never change.

Our knowledgeable staff has over 80 years of combined experience in removing radon from homes, businesses, schools, townhouses, condominiums, commercial, and government buildings. We currently have the largest and the most talented team of staff and technicians of radon mitigation professionals in the U.S. 

Common Radon Entry Points

Radon is a naturally-occurring, odorless and colorless gas that is produced by the decay of uranium in soil, rock, and water. Radon can enter the home through many different avenues. Below is a picture listing the many different ways radon can enter your home.

Home Radon Entry Points Diagram
  1. Cracks in concrete slab
  2. Spaces behind brick veneer walls that rest on uncapped hollow-block foundations
  3. Pores and cracks in the concrete blocks
  4. Floor-wall joints
  5. Exposed soil, as in a sump or crawl space
  6. Weeping (drain) tile, if drained to an open sump
  7. Mortar joints
  8. Loose fitting pipe penetrations
  9. Open tops of block walls
  10. Building materials such as soil and rock
  11. Well water (not commonly a major source in homes)

Radon System Piping Options

There are several methods to remove high levels of radon in your home or workplace. Radon mitigation systems ranging from active soil depressurization, passive radon mitigation systems, to waterborne radon mitigation systems. All radon mitigation systems have one goal in mind, and that is to reduce the radon gas level exposure inside your home. Radon system design and pipe routing specifications change from home to home depending on the homes building structure and the levels of radon.

Radon Mitigation System Diagram
Diagram of a typical radon mitigation system.

Testing After a System Has Been Installed

After your initial radon test and following the installation of your SWAT Environmental radon mitigation system, it is critical to test. This post-installation test confirms that radon levels have been reduced to non-hazardous levels.

Where does the test come from?

SWAT Environmental will provide a test kit with each installation performed. The Air Chek charcoal test kit can be implemented by any adult living in the home. Follow the kit instructions then simply drop the kit in the mail. (Postage and analysis costs have been prepaid by SWAT Environmental for your convenience.) Air Chek is the top provider of radon test kits in the United States.

How long do I have to wait to conduct my radon test?

Since radon can be affected by diurnal cycles (24-hour cycles that follow a full rotation of the earth), changes in temperature or atmospheric pressure that occurs from day to day, radon tests normally cannot be conducted in fewer than 48 hours. Most short-term charcoal radon test kits require a test period of 72 to 168 hours and should not be conducted sooner than 7 to 30 days after your radon mitigation system has been installed.

We recommend you wait 7 to 30 days to conduct the post-installation radon test because radon (Rn222) has a half-life of 3.8 days, meaning the picocuries per liter (pCi/L) (the unit by which radon is measured) reduces by approximately half every four days.

Your home naturally vents radon and existing radon naturally decays, but if your home has a high radon level, you will want to give your house enough time for the radon to clear, hence the waiting time before testing. And, your newly installed radon mitigation system is the only way to prevent new radon from entering your home.

What is my ideal test result?

The EPA recognizes the radon level 4.0 pCi/L as the official action level. Meaning, any building that has a level of 4.0 pCi/L or higher should be effectively “mitigated.” Ideally, you want your radon level to be as close to zero pCi/L as possible, but in reality the average radon level in the U.S. is about 1.3 pCi/L indoors and 0.4 pCi/L outdoors. Refer to your test kit results for recommendations on safe levels of radon or consult the EPA.

When and where do I conduct my test?

Ideally, you want to test under closed house conditions and on a day where there is little humidity. Closed house conditions mean that you should make a conscious effort to keep doors and windows closed in the house during testing, but you can still enter in and out of your home. Closed conditions should be kept for up to 12 hours before the test is started. The test should be conducted at least 36 inches from the floor and 12 inches away from exterior walls and frequently-used doors.

Remember that the test should not be conducted in the crawl space of the house, but rather in the room above or beside it.

Please keep in mind that you should avoid testing during heavy rainstorms. During a heavy rainstorm, your radon test can be skewed because of differences in atmospheric pressure and humidity.

We recommend that you retest your home every two years. Home radon tests can be purchased at your local hardware or home improvement stores or you can hire a professional radon tester.

How Your System Works

Always Protecting

Your SWAT Environmental radon mitigation system is designed to run 24/7 to maintain a balance of negative pressure and suction beneath your home. As the system continues to run, you can rest assured that the radon levels in your home will continue to remain low.


The pressure gauge on your radon mitigation pipe (located inline with the piping, between the fan and the lowest suction point) is designed to report activity within the radon mitigation system piping. The pressure gauge uses red dye inside of a “U” shaped clear plastic tube. The tube operates using the same physics as a straw in your drink – when the fan is sucking or moving air, the pressure gauge should be higher on one side. If the fan ever stops running, the pressure gauge will “zero out” and be even on both sides.


  1. Check the on/off switch power plug for the radon mitigation system. Power supplies are almost never consistently located in the same locations at every house because home designs vary, but the system’s power plug must utilize a credible power-source in your home.
  2. Go outside and check to see if there is a switch on the fan, if it is in the off position, turn it on.
  3. Walk through your home and check all of your GFCI outlets. There is a strong chance that a GFCI outlet has tripped in a location other than the power supply of the radon system.
  4. Make sure that the plastic tube to the pressure gauge is plugged into the pipe. If the plastic tube is not fed into the pipe the pressure gauge will not have access to the interior of the tube to execute the reading. (This usually happens when your gauge is zero and your fan seems to be running.)
  5. If none of the previous methods causes your fan to turn back on, then please contact our office and we will further assist you.

*IF YOU DISCOVER THAT YOUR RADON FAN IS NOT RUNNING, DO NOT PANIC. Studies have suggested that radon gas is most harmful over long periods of exposure. The chances of having immediate adverse health problems from radon are minimal, but don’t delay is scheduling service.

Radon Mitigation Piping

This component of the radon mitigation system is nearly maintenance here are a few common questions.

  1. SWAT Environmental’s radon mitigation systems do not have covers or bends at the tops of the discharge stack. This is because over the years we have found that the amount of force from the air flow coming from inside of the pipe is enough to keep 99% of debris and foreign objects out of the system and its piping.
  2. You may notice that your piping is starting to fade a little. Do not worry. This is a natural part of the PVC pipe and plastic. One good way to prevent this is to paint the radon piping. SWAT Environmental does offer system painting service.
  3. Condensation and moisture. There is a large difference between the temperature under your home and the air inside your home. If you see that there are water droplets on the piping in your basement or in your attic, please monitor. Excessive moisture can do damage to carpet and drywall and should this moisture become excessive, turn your system off and call the SWAT Environmental service department at 1-800-667-2366.

Sump Cover

About 50% of the homes that we service have sump pumps. Sump pumps protect homes from water damage. There are a couple of things to remember about the relationship between your sump pit and your radon mitigation system.

  1. Your radon mitigation system does not affect the performance of your sump pump. It is a common concern among customers that the amount of pressure beneath the sump cover can manipulate the functionality of the sump pump. This is not true. Your radon mitigation fan is designed to pull radon from your home, but it is not strong enough to compromise your sump pump. If your pump is not working properly, please contact a plumber for assistance.
  2. The sump cover is a clear, flexible thick plastic (Lexan) so you can see through to the pit. If you need to replace the sump pump, the caulking on the seal is sturdy but can be removed with a putty knife. If you remove the cover and break the seal, follow the instructions found on the SWAT sticker found on the cover you removed. Because the EPA’s Radon Mitigation Standards suggests a permanent seal on the sump pump cover, you will be required to replace the cover if it is removed. Sometimes the cover may shift or water can erode caulking on the seal. If this happens, be sure to re-caulk.
  3. If you have a pedestal sump pump, we highly recommend switching to a submersible sump pump because it allows us to adequately seal your sump. The float on a pedestal sump pump may get stuck on the clear cover over the sump pump.
  4. If you see your sump crock filling up with water please test your sump pump and try to pump the water out of the crock. If the sump does not turn on, please contact your plumber.

*SWAT Environmental releases all responsibility to the homeowner for the protection of their home due to water damage.

The Radon Fan

Your radon mitigation fan will run continuously and should never be turned off unless absolutely necessary. The fan is critical because it pulls the radon from the collection chamber through the piping and out of your home. If you turn off your fan for a significant length of time, you may see an immediate increase in your radon levels. It is very difficult to predict how long it may take for this to occur, so please leave the system on at all times. Through SWAT Environmental, you have an extended 5-year manufacturer’s warranty on the radon mitigation fan.


The content of this User Manual is based upon ASTM E2121-13 and radon industry best practices. Please note that while every effort was made to provide accurate information in a concise and understandable format, variations in state or local regulations or ordinances may impose additional design, operation, measurement, or inspection requirements which lie outside of the general scope of this content.

If you have questions regarding the specific regulations governing radon mitigation in your state, please contact your state radon program. Contact information for state radon programs can be found on the EPA website.