Radon Testing in Washington, DC

  • Radon Facts
  • Testing Methods

You can't see, smell or taste it. You may be drinking or breathing it. It's located everywhere, and at various levels.

Radon is a natural radioactive gas, which seeps into buildings from minute amounts of uranium that is present in all rocks, soil, bricks, and concrete. In highly concentrated amounts, radon can be harmful to the human body, but there is absolutely no need to panic. The following information will tell you what radon is, how to tell if it affects your home or workplace, and what you can do to reduce it. Remember, radon has been in the earth since the formation of our planet, and with proper testing and mitigation, we can keep everyone safe from its effects.

Health Concerns

Radon may cause cancer, and may be found in drinking water and indoor air. Some people who are exposed to radon in drinking water may have an increased risk of contracting cancer over the course of their lifetime, especially lung cancer. Radon in soil under homes is the biggest source of radon in indoor air and presents a greater risk of lung cancer than radon in drinking water. The Surgeon General has warned that radon is the second leading cause of lung cancer in the United States today. If you smoke and your home has high radon levels, your risk of lung cancer is especially high.

Radon In Air

Nearly one out of every 15 homes has a radon level the EPA considers to be elevated: 4.0 pCi/L or greater. The U.S. average radon-in-air level in single family homes is 1.3 pCi/L. Because most people spend as much as 90 percent of their time indoors, indoor exposure to radon is an important concern.

Most indoor radon comes into the building from the soil or rock beneath it. Radon and other gases rise through the soil and get trapped under the building. The trapped gases build up pressure. Air pressure inside homes is usually lower than the pressure in the soil. Therefore, the higher pressure under the building forces gases though floors and walls and into the building. Most of the gas moves through cracks and other openings. Once inside, the radon can become trapped and concentrated.

Openings which commonly allow easy flow of the gases into the home or workplace include the following:

  • Cracks in floors and walls
  • Gaps in suspended floors
  • Openings around sump pumps and drains
  • Cavities in walls
  • Joints in construction materials
  • Gaps around utility penetrations (pipes and wires)
  • Crawl spaces that open directly into the building

A variety of methods are used to reduce high radon levels in buildings. The system that is best for you depends on several factors. Buildings in New England are generally categorized according to a foundation design of basement, slab-on-grade (concrete poured at ground level) or crawl space. Some buildings use a combination of these and require installation of more than one type of radon mitigation system.

Radon In Water

Radon in water is a new and emerging issue. There is not as yet a standard national action level for radon levels in water, though the EPA's limit of 300 pCi/L for radon in municipal water systems will be in effect soon. In a strange twist, the EPA now says if water suppliers launch a multimedia campaign through public service announcements to help the public better understand the health effects of radon, they will be allowed to have up to 3,000 pCi/L of radon in their water. Please keep in mind that many states and municipalities maintain their own standard levels that may be higher or lower than the EPA's guidelines.

Radon in water is not as dangerous from a public health standpoint as radon in air. Ingestion of radon-laden water causes approximately 18 cases of stomach cancer annually. Inhalation of radon gas and radon decay products causes between 15,000 & 22,000 lung cancer deaths annually.

The problem with radon in water is that a great deal of it finds its way into the air. As a rule of thumb, each 10,000 pCi/L of radon in your water creates an additional 1 pCi/L in your air.

Here is the scenario: Radon is fairly soluble in water. Deep wells get their water from within bedrock, shale, granite and other rock deep beneath the surface... the same place radon comes from. The radon gas dissolves in the water and works its way up to your home when you bathe, wash the dishes, do laundry, etc. When the water becomes agitated, the dissolved radon gas is freed into the air.

You should test for radon in water if the following circumstances exist:

  • A radon-in-air test was above 4.0 pCi/L
  • The water supply is from a private well or a public water supply that gets its water from deep wells.

Above-ground water sources such as reservoirs typically do not have radon problems.

Protect The Investment is ready to help you test your property for radon. We are ready when you are! Our company provides the fastest and most accurate testing services available. Our various testing equipment allows us to provide every type of radon test available.

There are several types of short-term devices that are used for testing the level of radon in the air. A short-term test is typically performed over a two-to-seven-day period. This test gives an indication of levels that can be expected over the long term. We typically perform long-term tests (90+ days) immediately following the installation of a mitigation system.

Charcoal Canister

Activated Charcoal A charcoal canister is a small, metal, disc-shaped device. When the test starts, the canister is opened and placed:

  • In an interior area closest to the soil, typically the basement here in the Northeast
  • About 2 feet off the floor
  • In an undisturbed area
  • Under closed-house conditions

​The canister is left in the basement for two to seven days. At the completion of the test, the charcoal canister is sealed up and mailed off to a laboratory for evaluation. The results are available a few days after receipt by the lab. It is important that once the test begins that the protocol be strictly followed to obtain the most accurate information. For example, a test kit evaluated 30 days after the specified exposure time will have a much lower radon reading than one that was evaluated immediately following the two-to-seven-day test period. This is because the test is evaluating radon, which has a half-life (when its radiation is strongest) of 3.8 days. The longer the test evaluation is delayed, the lower the level that will be detected. The main advantage of this screening test is its low price. Several disadvantages are that:

  • ​It is easily tampered with
  • Only offers an average radon level reading
  • May not be accurate
  • Takes a long time to receive results as compared to other methods.
Liquid Scintillation Vials

Liquid Scintillation A vial with a small amount of activated charcoal is placed in the lowest livable area of the home. Radon becomes trapped in the charcoal. Upon completion of the test, a lab places the charcoal into a second vial full of liquid scintillant. After approximately 4 hours in the liquid, the radioactive decay of radon is visible through light flashes. The light flashes are counted with a device, rendering the actual radon level in your home.


Continuous Radon Monitor A CRM is a computerized device that takes a radon level reading once per hour. The CRM has a similar testing protocol as the charcoal canister. There are several major advantages to this method:

  • Results are obtained immediately after the completion of the test. A hard-copy printout of hour-by-hour readings, as well as an average, is immediately available to you.
  • The CRM has a tamper-detection mechanism. If the device is disturbed at all, we are notified through the printout.
  • Results are much more accurate than charcoal canisters
  • CRM testing is more expensive than charcoal canister testing, yet the improved accuracy as well as peace of mind typically make the cost worthwhile

Protect The Investment highly endorses the use of the CRM method of testing during real estate transactions. CRMs give you instant results. CRMs are also more resistant to tampering and are more accurate than charcoal canisters.

E-PERM® System

E-PERM®s are the most popular of all the radon detectors submitted to the U.S. EPA for its Radon proficiency Program. They're also the most accurate. Since 1991, more than 90% of the E-PERMs submitted have "passed" the EPA's performance tests...even more than the electronic Continuous Radon Monitors. A true integrating detector, the device can measure fluctuating radon concentrations regardless of extreme temperatures or humidity. The U.S. Postal Service and several branches of the U.S. Armed Forces have chosen E-PERMs for surveys of public properties in the U.S. and overseas.

Getting Tested

To schedule a test, simply contact us at (202) 422-3821. When calling, please have the following information available:

  • Property location
  • Type of property (single family, etc.)
  • Basement, slab-on-grade, crawl space?

We maintain a large number of testing devices and are typically available to begin testing the day after you contact us. Sometimes we are available the same day. We will do everything we can to accommodate you. We maintain early morning, afternoon and evening appointments as well as weekends. Your satisfaction and your peace of mind are important to us. Testing takes 48hrs, the time we drop off the machine will be the time we pick it back up.

What It Costs

We do our best to keep your cost for testing among the lowest in the region. Charges typically range from $150 up to $225 for testing with a Continuous Radon Monitor. We keep our prices low as it:

  • Saves you money
  • Promotes a clean and healthy living environment.