Protect your health. Test your home.



St. Louis Radon Testing

CRM - Continuous Radon Monitor Testing 

  • Great for real estate transactions
  • 48-hour testing with immediate results
  • Graphed hourly results
  • Most preferred short term testing option
  • Professional staff with Supra keys for real estate transactions
  • Next day and Saturday appointments available.
  • Appointments can be scheduled on-line. Click on the tab on in the top right corner 

We offer professional radon measurement with the 1028 Sun Nuclear Continuous Radon Monitor. Test results include a grahical representation of the radon concentration for every hour deployed, along with overall and US EPA average readings.

St. Louis Radon's monitors are calibrated annually by an EPA approved laboratory. They're also subject to QC/QA program and continuously checked throughout the year to verify accuracy.

CRM machines have tamper resistant features that detect device movement.

continuous radon monitor test

Radon Test Results - Example 1

E-PERM System - Electret Passive Environmental radon/radiation monitor

  • An electret ion chamber
  • An E-PERM is comprised of two components
    • an electret
    • a special chamber that will allow ionization to occur
  • Great for real estate testing
  • 48-hour testing with same day results 
  • Next day and Saturday appointments available


Radon Gas in Missouri

The US Surgeon General strongly urges every home, school and office in the US to be tested for Radon gas. 

About 1 in 15 homes across the United States is estimated to have Radon levels exceeding the EPA's action level. 1 in every 5 homes in Missouri are believed to be above the acceptable EPA limit.

Most radon mitigation systems in Missouri are installed in homes that had initial readings between 4-10 pCi/L. Homes are occasionally above 20 pCi/l, however, we have mitigated homes with over 80 pCi/L. 

All homes should be tested in a real estate transaction, even if they have a radon mitigation system. Homes with radon systems should be retested at least every two years.

Testing is the only way to know if you have elevated levels of radon. 


The first step to help ensure the safety of you and your family’s health and safety is to have your home tested for radon. At St. Louis Radon, our professional testers deploy the latest in computerized electronic real-time radon monitoring technology to provide you with a comprehensive report, including a complete visual graph of radon level data points as recorded over a 48-hour sampling period.

Learn More About Testing


If testing indicates levels of radon that require action, our team of engineers and technicians will design and install a custom radon mitigation system to safely and effectively redirect radon and other soil gasses out of your home. We also take additional measures to seal and close other possible breaches in the foundation that could let soil gasses into the through cracks or drain tiles systems.

Learn More About Mitigation

New Construction

With new home construction projects, it is crucial to determine the level of radon that may be present in the soil before the home is built. It’s also critical to have the new home retested for potential radon concentrations immediately following occupancy. We also highly recommend installing an Active Dampness Control System (ADC) with every new build.

Learn More About New Construction