Protect your health. Test your home.



St. Louis Radon Testing

CRM - Continuous Radon Monitor Testing 

  • Great for Real Estate Transactions
  • Only 1 Test Period Needed
  • 48 hour Testing with Immediate Results
  • Graphed Hourly Results
  • Most preferred short term testing option
  • Very accurate results reported in hourly increments
  • Professional Staff with Supra keys for real estate transactions

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.

Tests run for a period of 48 hours, and same day appointments are often available. Continuous radon monitor tests are a great way to get the most accurate measurements available. Please let us know if your home has a crawl space or room addition.

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

Radon Gas in Missouri

The US Surgeon General strongly urges everyone in the US to test for Radon gas.

Levels between 4-20 pCi/l are very common. Homes are only occasionally far above 20 pCi/l, however we have fixed Missouri homes with continuous spikes over 80 pCi/L. It would take approximately 2,500 radon atoms per square inch to create a radon concentration of 4pCi/L.

You cannot estimate radon levels based upon the homes age, location, design or test results from a neighbor's home.

  • There are no symptoms from radon exposure.
  • You can't see radon.
  • And you cannot smell it or taste it.

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

Radon is measured in PicoCuries per Liter of Air, (pCi/L). Pico = one trillionth.

1pCi/L = 2.22 decays per minute per liter of air. So then, 4pCi/L equals 10 decays per liter of air per minute.

Testing is the only way to know.

About 1 in 15 homes across the United States is estimated to have Radon levels exceeding the EPA's action level. One in every 5 homes in Missouri are believed to be above the acceptable EPA limit. The only way to know if a home has a problem with radon gas is to test.



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