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Radon FAQ

The US EPA, the Surgeon General, the American Cancer Society, the American Lung Association, and the World Health Organization recommend that all homes be tested for Radon.

What is Radon and why is it so dangerous?
Radon is a naturally occurring radioactive gas that is in all homes and is a proven carcinogen. It comes from the decay of Uranium which is found in nearly all soils. Radon is colorless, odorless, and without taste. Lung cancer is the only known effect on human health from exposure in air. Radon is the number one cause of lung cancer among non-smokers, according to US EPA estimates. Overall, radon is the second leading cause of lung cancer.

What is the measuring scale and what is considered a "high level" of Radon?
The measurement used for radon testing is pico Curies per liter (pCi/L). The US EPA recommends that homes be fixed if the radon level is 4.0 pCi/L or more. Also, the US EPA recommends that you should consider lowering the level if the level is between 2.0 pCi/L and 4.0 pCi/L.

How is the Radon level measured?

Since Radon in a home cannot be detected by human senses a testing device is used. There are two types of measuring devices, passive and active. We use an active electronic continuous radon monitor (CRM). Using an active electronic CRM ensures the accuracy of the test data due to its tamper resistance features.

How does Radon get inside a home?

Radon can enter a home in many different ways:

  1. Cracks in the solid floor.  

  2. Construction joints.

  3. Cracks in basement walls.

  4. Gaps in suspended floors (crawl space).

  5. Gaps around service pipes.

  6. Cavities inside a wall.

  7. Well water (this is rare).


In very rare cases, Radon can enter through the home's building material.


What are the testing protocols for measuring Radon levels in a home?

There are 2 US EPA testing protocols. One protocol is for a real estate transaction. Basically, this protocol takes into consideration the time sensitivity of a real estate contract. The minimum time for this test is 48 hours. The testing device goes to the possible living area of the home. The other protocol is for a concerned citizen. This protocol can take longer. There is an initial test and then based on the results there could be a follow-up test. The testing device goes into the lowest living area of the home.

How is the Radon level lowered in a home?

It is relatively simple. If the home has a basement, a subslab suction system

is the most common way. If the home has a crawl space, an air tight membrance

is used over the ground and a suction system is installed. Most radon reduction

systems include a monitor that will indicate whether the system is operating

properly.  In addition, it’s a good idea to retest your home every two years to be

sure radon levels remain low.


  • We have been performing Radon tests for over 30 years.

  • Our highest test result was 75 pCi/L. 


External links:


Information from the US EPA about Radon testing for a real estate transaction: Home Buyer's and Home Seller's Guide to Radon.

Information from the US EPA about Radon for a concerned citizen: A Citizen's Guide To Radon.

Information from the Environmental Law Institute & US EPA for tenants: A Radon Guide For Tenants.


Information from the US EPA about Radon testing for a real estate transaction: Guía del Radon para el Comprador y Vendedor de Viviendas

Information from the US EPA about Radon for a concerned citizen: Manual Informativo Sobre El Radón.

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