Ashburn, VA

Average cost for Radon Mitigation ranges from
$500 – $4,700

The average cost for radon mitigation is $2,000. Hiring a radon specialist, you will likely spend between $500 – $4,700. The price of radon mitigation can vary greatly by region (and even by zip code). View our local radon specialists or get free estimates from pros near you.

How much does radon mitigation cost?

Author: Daniel W.
Millions of people ask HomeGuide for cost estimates every year. We track the estimates they get from local companies, then we share those prices with you.

What is Radon?

Radon is a colorless, odorless, tasteless, radioactive gas. It occurs naturally in tiny amounts, and it is the immediate decay product of the element radium in soil and water, and uranium and thorium in the soil.

Compared to the half-life (the time required for a quantity to reduce to half its initial value) of uranium and thorium of several billions of years, the half-life of radon is only 3.8 days, but it will always be present because it is continually being created.

Locations of radon

Geographically speaking, the detectable levels will vary from place to place, and, typically, it is a known issue wherever it has been detected. Apart from it seeping up through the earth in different parts of the country, or residues from the production of petroleum or natural gas, radon is produced from the decay of radium-226 and is found in metamorphic rocks such as granite and, to a lesser degree, in limestone.

On top of the radon gas that decaying elements produce, radon itself produces dust particles as it decays which, if inhaled, can also cause lung cancer. In the US, the highest concentration of radon levels has been measured in Iowa and the Appalachian Mountains in Pennsylvania.

You can find an interactive map on the Environmental Protection Agency’s website detailing the levels detected for each state, broken down by counties into three different zones.

Radon Health Risks

The risks from radon were discovered as early as 1530, when it was described in the mining industry as a wasting disease and was responsible for the move to allow for ventilation to help stop what was then called mountain sickness.

Because radon is a gas and is easily inhaled, it poses a severe health risk, which makes it the second leading cause of lung cancer (after cigarettes) in the US—responsible for over 21,000 deaths annually. Of that number, 2,900 have never smoked, which makes it the leading cause of lung cancer for the population of nonsmokers.

Of all radon cancer-related deaths in a given year, 89% are from lung cancer and the other 11% are from stomach cancer from radon delivered through drinking water.

Radon in the home

High levels of radon in residential homes were first discovered accidentally in 1985. The natural seepage rises up through the soil into any crack in the foundation, walls, wall cavities, construction joints, spaces in suspended floors, and the water supply. Depending on the cracks in the rock under a home, the levels of concentration will vary—anywhere from your entire property, to one corner of your garage, to only under your yard. Levels will vary and change throughout a home based on the ventilation flow.

Radon Mitigation

Radon Testing

Across the nation, there is only a total of about 6% of homes that have concentrated radon levels inside the home, and the detection process begins with testing. Radon mitigation is the process to reduce indoor radon contamination issues and is carried out by professionals.

Based on current data, while a large number of states in the US don’t register what would be considered dangerous levels of radon, the Environmental Protection Agency recommends all homes be tested for the presence of radon. There are certain counties in some states, as detailed on the EPA website, where this is really important because of previously detected seepage in that area.

Because you cannot see it, smell it, or taste it without the right equipment, you would never know it is in a home. While you can purchase a radon detection kit from hardware stores, or online, many states also offer very inexpensive or no cost radon testing devices through taxpayer-funded incentives. The older a home is, the higher the need to address the issue.

A professional radon mitigation specialist will detect the levels of radon quickly. Look for one certified with the American Association of Radon Scientists and Technologists (AARST) and a member of the National Radon Proficiency Program (NRPP) through the National Environmental Health Association.

“The test is a minimum 48 hours under closed home conditions to determine if the home has Radon in excess of 4pCi/L (4 pico curies per liter of air), the EPA’s recommended action level.” -- Integrity Building Inspections in Lee’s Summit, MO

Cost of Radon Gas Testing

Single-use testing kits can be purchased for less than $20, and ongoing testing systems typically cost between $100 and $200, depending on their features. For the single-use test, a popular solution works by leaving the radon sampler in an open area in the lowest part of the home for 2–4 days and then mailing off the unit to be tested, with the results e-mailed within 72 hours.

Ongoing monitoring, which is recommended in areas where radon buildup is a known risk, is available in a product that you leave plugged in to deliver continuous testing. This product will continuously sample the air for radon and can include features like showing you the averages for the previous seven days, as well as an audible alarm if the levels rise above the EPA safe levels of 4 pCi/l.

What can be done?

Because this is a naturally occurring process under the surface of the earth, there is nothing you can do to stop it; however, you can take steps to reduce the buildup of radon gas from the air supply in commercial and residential buildings, and from the water supply, through a process called radon mitigation.

Radon Mitigation

With modern testing devices, and processes to eliminate the seepage, all homes’ radon levels are fixable, with most homes fixed within one day. Many companies offer pledges with their services, like Alta Inspection Services in Downers Grove, IL. They say “We pledge to complete the inspections and provide written reports within 1–3 days after being contacted. ... We have extensive experience in new construction, environmental issues, new materials and product performance.”

Sealing and extraction

While typically a good place to start, addressing the cracks in the foundation by sealing them is not a complete solution to eliminate radon gas buildup on its own. It requires other mitigation measures such as various specialized ventilation systems and charcoal water filtration systems.

The PSA says it does not recommend the sealing as the only treatment to reduce radon “because, by itself, sealing has not been shown to lower radon levels significantly or consistently.”

According to the EPA’s guide to radon, the primary method of extraction is through ventilation—using fans and a system of pipes—to extract radon from beneath the house and release it into the air outside the home, above the roof, where it dilutes.

In the section “How to fix your home” from the EPAs Consumer's Guide to Radon Reduction, it says:

“Ventilation systems can utilize a heat exchanger or energy recovery ventilator to recover part of the energy otherwise lost in the process of exchanging air with the outside.”

In reference to crawlspaces, the EPA mentions:

“An effective method to reduce radon levels in crawl space homes involves covering the earth floor with a high-density plastic sheet. A vent pipe and fan are used to draw the radon from under the sheet and vent it to the outdoors. This form of soil suction is called submembrane suction, and when properly applied is the most effective way to reduce radon levels in crawl space homes.”

The two leading approaches for radon reduction are ASD (active soil depressurization) and MV (mechanical ventilation). ASD is the typical choice in treating radon that seeps upwards in the ground under a home, while MV is used to treat radon that comes from building materials. Depending on the solutions employed for radon mitigation, some can result in the introduction of mold from the increased interior air moisture and humidity.

Cost of sealing and extraction

While not proving to be 100% effective on its own, sealing cracks in your home’s foundation could be accomplished for as little as $200, depending on the construction of your home.

Extraction systems that transfer the radon gas from under your home to the air above your roof can range from $500 to $2,500, depending on the type of foundation.

The fans that are installed as part of the extraction process typically carry a five-year warranty, and when they need to be replaced, expect to pay between $200–$300. With the use of extraction fans as the essential and most productive part of your mitigation strategy, there will be an increase in the power consumption and resulting utilities expense for your home. This will vary in correlation to the levels of buildup the contractor needs to remove and on the size of your home.

Radon in the water

If you already know there is radon contamination in your water and are moving forward with treatment, then a good contractor will have water testing included in the service. If you are not sure and want to test your water yourself, you can buy a radon water test kit at a hardware store and send off your water sample to be tested by a lab.

Surface water which comes from lakes, rivers, and reservoirs is generally not a source for radon gas delivery because the radon gets released into the air. You can also be confident that your local water municipality has taken care of getting water to your home radon free, but water contamination might occur if your water source is a well or draws from an aquifer.

The EPS has set forth guidance about regulations pertaining to any community water supplier that delivers water to 25 or more residents, but they do not regulate private well water sources.

Radon Mitigation Systems Cost

In treating water for radon contamination, systems called point of entry devices are put in place between the water mains supply and your home. These devices are either GAC or aeration devices. Granular activated carbon (GAC) filters are the least expensive of the two and use carbon to filter out the radon as it passes through the filter. Aeration devices send a stream of bubbles through the water, and extractor fans carry the radon gas out into the outside air.

Average cost: $1,100–$4,700 for a water treatment solution.

When choosing your radon mitigation specialist:

  1. Even if you have conducted testing, or a previous resident has had radon testing carried out, good contractors will do their own testing.
  2. In addition to testing, they will do a complete visual inspection at the home, to include the foundation and home structure, to determine the most suitable system needed to ensure the safety of the inhabitants of the home. Consider using a contractor familiar with all aspects of home inspection.
  3. They will provide recommendations for the installation of a radon mitigation system that complies with all EPA guidance and regulations specific to your geographic location.
  4. They will leave the system installed, with all relevant labels attached, and provide instructions on its use.
  5. After the radon mitigation system has been installed, they will run another set of tests to verify the effectiveness of the installed system, when the results are compared to the first set of test results.
As with any service in this price zone, get between 3–5 bids before deciding on a contractor, and ask for and check out the ratings on the Better Business Bureau to give yourself peace of mind and to avoid any unpleasant additional costs.
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