Radon testing in Denver

Buying a home is an exciting time in anyone’s life. After months of searching, you finally find the perfect house in the ideal neighborhood. Before signing on the dotted line, it’s important to have a home inspection done first. This will identify any issues or needed repairs so you know exactly what you’re getting into with your new property.

One critical test that should always be included is a radon inspection. This colorless, odorless gas is the second leading cause of lung cancer in the United States. Denver homes in particular are susceptible due to the region’s unique geology. Read on to learn why Radon testing in Denver is so important for Denver homebuyers and what steps you need to take to keep your family safe.

What is Radon?

Radon is a radioactive gas that is formed from the natural decay of uranium in soil and rock. It’s invisible, has no smell or taste, and can only be detected through specialized tests. Radon gas seeps into homes through cracks in the foundation, pipes, drains and other openings. Once inside, radon can become trapped and accumulate to dangerous levels.

According to the Surgeon General, radon is the second leading cause of lung cancer in the United States. Only smoking causes more lung cancer deaths. The EPA estimates that radon contributes to over 20,000 lung cancer deaths per year.

Exposure to radon does not cause any immediate symptoms. Lung cancer can take years or even decades to develop after exposure. This makes testing critical to detect high radon levels before health complications occur.

Why is Radon a Concern in Denver?

Geography and geology make radon more prevalent in some regions than others. Denver’s location in the Rocky Mountain region puts it at especially high risk. Here are some reasons why:

  • Uranium-rich soil: The rocks and soil around Denver contain higher than average levels of uranium. As uranium decays, it produces radon gas which can enter homes.
  • Cracks and openings in bedrock: Denver homes are built on bedrock rather than soil. Natural cracks and openings in the bedrock provide entry points for radon gas to seep up from below.
  • Cooling effects: Denver’s cool climate causes temperature variances between the home and soil underneath. This creates a “chimney effect” which draws radon gas into the home.
  • Mine shafts: Old abandoned mine shafts under parts of Denver can channel radon up to the surface.
  • Radon zones: The EPA has designated certain areas of Colorado, including Denver, as “Zone 1” radon zones. This means they have a higher potential for dangerous radon levels.

According to Colorado state data, around 50% of homes in the Denver metro area have radon levels above the EPA action threshold. This makes testing critical for all Denver area home buyers.

EPA Radon Guidelines

The Environmental Protection Agency (EPA) sets guidelines and recommendations for radon levels based on extensive research. They categorize radon levels as follows:

  • Below 2 pCi/L (picoCuries per liter): Low potential for health risk
  • 2-4 pCi/L: Moderate potential for health risk
  • Above 4 pCi/L: High potential for health risk

The EPA identifies 4 pCi/L as the recommended “action threshold.” At this level, they advise homeowners to take steps to reduce radon. However, there is still some risk between 2-4 pCi/L. 

The EPA recommends fixing levels as low as reasonably achievable, ideally below 2 pCi/L.

It’s important to note that these guidelines are based on living in the home full time. For homes only occupied part of the year, the EPA recommends taking action at a lower level of 2.7 pCi/L.

Types of Radon Tests

Radon testing in Denver involves using a specialized device to measure the amount of gas in the air. There are two main types of radon tests:

Short-Term Test

This quick test remains in your home between 2-90 days. A charcoal canister device or alpha track detector is placed in the lowest level of the home. After the designated time, the device is sent to a lab for analysis.

Pros: Provides a snapshot of radon levels. Relatively quick and inexpensive.

Cons: Only measures radon during the testing period. Levels can fluctuate daily and seasonally. Could miss high readings.

Long-Term Test

A long-term test remains in the home for more than 90 days. A small monitor or film is used which continuously tests and averages radon levels over time.

Pros: Gives a clearer picture of radon levels over different seasons. More likely to detect highs.

Cons: Takes longer to complete. Slightly more expensive

For real estate transactions, the EPA recommends doing a long-term test. Long-term tests give a more complete view of the home’s year-round radon levels. However, if timing is critical, a short-term test is better than no test at all.

When to Test Radon Levels

Ideally, radon testing should be done as part of pre-purchase home inspections. Knowing radon levels in advance allows you to negotiate with the seller if high levels are found. There are also certain scenarios which require retesting after moving in:

  • Living space additions – A new living space like a basement could alter radon levels. Retest after the addition is completed.
  • Major renovations – Significant renovations to the foundation or HVAC system can also impact radon entry. Test again after work is done.
  • Previous owner declined testing – Many buyers inherit untested homes. Conduct a test as soon as possible.
  • Fixing an identified problem – Follow up testing ensures radon mitigation systems reduced levels.
  • Routine re-testing – The EPA recommends testing your home for radon every 2 years. Levels can rise over time.

Pro Tips for Radon Testing

Follow these tips to ensure you get helpful results from a radon test:

  • Test the lowest level – Radon concentrates in lower areas. Place the detector in the lowest livable space of the home.
  • Close windows and doors – Closing up the home provides a more accurate reading. Don’t tamper with or move detectors during the test.
  • Run HVAC systems – Operate home heating and cooling systems normally so air circulates the home.
  • Test long-term – For home purchases, only long-term 90+ day tests give a full picture of average radon.
  • Use an accredited lab – Have an industry certified lab analyze the detector to ensure accuracy.
  • Retest when needed – Follow EPA guidelines on when to retest radon levels in the home.

Radon Mitigation Strategies

If radon levels are found to be 4 pCi/L or higher, mitigation steps should be taken to reduce concentrations in the home. Here are some common radon reduction strategies:

Active Soil Depressurization

This is the most effective mitigation method. A pipe and fan system draws radon from under the home and vents it outside before it can enter. A qualified radon mitigation contractor should install the system with a vent pipe running from below the foundation to above the roof.

Air-to-Air Heat Exchanger

An air-to-air heat exchanger uses a fan to pull radon up from below before it enters the home. The radon gets vented outside while heat gets recycled back indoors. Less effective than active soil depressurization but requires minimal work inside the home.

Sealing Cracks and Openings

Sealing all cracks in the foundation floor and walls can help reduce radon entry points. However, radon can still penetrate concrete so this is usually only done in combination with other mitigation strategies.

Sub-slab Depressurization

A vent pipe with a fan draws radon from beneath a concrete slab foundation before it can rise into living spaces. Often used in homes built on concrete slabs rather than those with basements or crawl spaces.

Drain Tile Suction

If drain tiles run under the foundation they can be a conduit for radon. A suction fan pulls radon from the drain tiles before it can rise into the home and vents it outside.

In some cases, radon levels may be so severe that a mitigation system cannot reduce them enough. If levels remain dangerously high even after a system is installed, it’s a good idea to consult a certified radon mitigation professional for advice and additional solutions.


Given Denver’s geology, Radon testing in Denver is a key component of any pre-purchase home inspection. Elevated radon levels are common but easy to miss without proper testing. Left undetected, this radioactive gas can create substantial health risks. But with the right knowledge and testing, buyers can identify and fix high radon before it becomes a problem. Be sure to consult a qualified Denver home inspector who includes thorough radon screening. This provides vital data so you can make informed decisions about any necessary mitigation measures. With the right precautions taken, you’ll be able to rest easy knowing your new Denver area home is not exposing your family to this silent hazard.

By Mohsin Ali

My name is Mohsin Ali. I Am admin of https://techkstory.com/ with 4 year experienece in this field. I am working also as a reseller and I have large number of high quality guest post websites available Email: techkstory.com@gmail.com

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