Testing for Real Estate Transactions

Overview of testing procedures

You may want to have a radon test done by a certified radon tester instead of doing it yourself with a kit, especially if the test is being done as part of a real estate transaction. A certified radon tester knows the proper conditions, test devices, and guidelines to obtain reliable radon tests and will follow U.S. EPA protocols. He or she will evaluate the home and recommend the best approach for reliable results.

In addition, a certified tester will explain proper testing conditions, and the necessity of cooperation of occupants during testing. The tester will analyze and report results. By using an independent, third party tester, results will be provided by someone not involved in the real estate transaction.

For purposes of real estate transactions, radon professionals often utilize a short-term test to determine the radon potential of a home. These test devices are placed in a building for a minimum of 48 hours.

Both passive and active test mechanisms are available. Passive tests do not require electricity but do require sending the test to an approved laboratory for analysis. They usually consist of an activated charcoal device. Active radon tests require power to operate, and usually referred to as "continuous monitors" that will give results over a set period of time and indicate changes in radon concentrations.

Proper short-term testing is dependent on correct placement and conditions within the home during the test. "Closed-house conditions" are very important! The windows and doors must be kept closed (except for normal entry and exit) a minimum of 12 hours before and during the entire testing.

In the case of real estate transactions, the test device must be placed in the lowest area of a home that is "suitable for occupancy." Brokers and agents must discuss this point with their clients and customers so a decision can be agreed upon, based upon the future use of the dwelling by the buyer. [For example, if the house in question has a finished basement that has not been used by the seller but will be used by the buyer, this would be the best location for the test.] Crawl spaces are not appropriate test locations. Areas in the home with high humidity levels and increased ventilation are also not good locations (such as bathrooms and kitchens). A test device must be placed at least 20 inches above the floor, in a location where it will not be disturbed.

The Radon in Real Estate Testing Checklist details all of the steps involved in obtaining reliable real estate tests, following U.S. EPA protocols.

If radon concentrations are unacceptable to a buyer - and certainly if they are at or above 4 pCi/l - the home should be mitigated. The parties involved will have to discuss the timing and costs of mitigating the home. This is no different than discussing leaky roofs, broken stairs, or cracked windows!

If the initial short-term test indicates a level at or above 4 pCi/l, there are several options as to what to do next, especially relative to a real estate transaction that may be in process. Keep in mind several important facts:

  • Homes with radon can be reliably reduced to levels less than 4 pCi/l.
  • Most mitigation systems can be installed in one day by a qualified contractor, but crawl space foundations may take two days to complete.
  • Repairs take 24 hours to take effect and before re-testing should occur.
  • Radon reduction is easily affordable. Radon problems are generally simple and cost-effective to repair. Mitigation systems average $2,500 to $3,800, but the price per home will depend upon the type of foundation, the size of the home, and the distance to travel to the mitigation location.

The most effective and cost efficient method for radon reduction is Active Soil Depressurization. This method collects radon from beneath a building before it enters the structure, and vents the radon safely to the outside. The particular steps required to do this depend upon the building's foundation. See How to Fix a Radon Problem.

Using a qualified tester

In real estate transactions, we do not recommend that the seller, buyer or real estate professional conduct the testing. Testing should be done by a third party, therefore, you may want to have a radon test done by a qualified (certified) radon tester instead of doing it yourself. A qualified tester can:

  • Evaluate the home and recommend how to test it.
  • Explain how to keep your home in the proper condition during the radon test.
  • Analyze the data and provide an independent test result.

A radon tester should be able to verify that the following steps have been taken. If this is not possible, a new radon test should be performed.

  • Prior to testing, occupants were notified regarding the importance of proper testing conditions, and given written instructions or information explaining directions.
  • If a homeowner or homebuyer took the measurement, the test was performed with a radon measurement device listed with the Radon Measurement Proficiency (RMP) Program, and manufacturer's instructions were followed.
  • That he or she is a certified radon professional. See "To locate a certified radon tester" below. The tester's ID number should be clearly visible on the radon report.
  • The test included methods to prevent or detect interference with both testing conditions and the test device.
  • The radon test was at least 48 hours long. (Some devices must be placed for more than 48 hours.)
  • The EPA recommends that initial short-term radon testing be performed under closed-house conditions. This means all windows were kept closed and except for normal entry and exit, exterior doors have been shut.
  • Fans or other machinery bringing air in from the outside should not be running (unless part of an existing permanent radon mitigation system). The home's heating and cooling systems should operate normally during testing, using air conditioning units that only recirculate interior air. Evaporative coolers (such as swamp coolers) are to be off, in addition to "whole" house fans.
  • For short-term tests, closed-house conditions must be maintained for at least 12 hours before and during the tests. Test devices should not be disturbed at any time during the test.

Three testing options

There are three options of testing that are acceptable for real estate transactions:

  • Take two short-term tests at the same time in the same location (4 inches apart) for at least 48 hours. A realtor should never do a test! 
  • Take an initial short-term test for at least 48 hours. Immediately upon completing the first test, do a second test using an identical device in the same location as the first test. Only the homeowner should do a test - not a realtor.
  • Test with a continuous monitor for at least 48 hours. A certified tester utilizes EPA testing protocols and should include steps to prevent or detect interference with the test device. They can provide test results immediately after the 48-hour test.

To locate a certified radon tester

Contact or visit the following:

Radon test device placement

EPA recommends placing testing the device(s) in the lowest level of the home that could be used regularly, whether it is finished or unfinished. Conduct the test in any space that could be used by the buyer as a bedroom, play area, family room, den, exercise room, or workshop.

  • Do not test in a closet, stairway, hallway, crawl space, or in an enclosed area of high humidity or high air velocity, such as a kitchen, bathroom, laundry room, or furnace room.

Is Escrow an Option?

Many aspects of radon mitigation may be negotiated, just as with other aspects of a real estate transaction. For a buyer, it is sometimes advantageous to have the ability to make choices regarding the installation of a mitigation system. Funds may be escrowed for this purpose, but a buyer can always be confident that radon can be mitigated to less than 4 pCi/l, regardless of a seller's willingness or ability to financially contribute to this issue. For a seller it may be advantageous to escrow funds that allow for testing for a full year to obtain the annual average radon concentration (the EPA Action Level of 4 pCi/l is based on an annual average) rather than make a decision to mitigate based on a short-term screening test.

Contingencies regarding radon may be included in a transaction, however, they should be specific to acceptable levels of radon, not upon testing itself.

In a contingency clause, it is important to be specific. Some helpful points to remember as an agent or broker:

  • All radon tests will show some amount of radon.
  • Consider discussing whether or not radon mitigation will be an acceptable option.
  • Remember that mitigation is a well-known science, with additional benefits to indoor air quality beyond radon reduction.
  • Tests performed by homeowners, or by individuals who are not listed as certified, may not be reliable. Recommend that testing and mitigation be performed by individuals listed with the National Environmental Health Association's radon proficiency program or with the National Radon Safety Board.
  • Costs of installing radon mitigation systems are based as much on aesthetics as they are on radon readings. A system contracted by the seller may not be as attractive as the buyer might prefer, or as energy efficient. A buyer and/or seller could pay for more expensive pipe routings, or even to have the entire system enclosed to make the system less conspicuous. Optional costs for aesthetics can be broken down for negotiation purposes.
  • The buyer and/or seller may consider extensive caulking and sealing to further reduce radon and the energy impact of such a system.

Many radon mitigation contractors will provide bids with guarantees to reduce radon levels to less than 4.0 pCi/l. This may allow for adequate funds to be escrowed for the home to be fixed after the buyer moves in. Another option is to make funds available for reducing radon if a long-term (91 days or longer) test device is placed in the home. A long-term test can provide a more accurate average of radon risks to which an occupant is exposed under normal living conditions (i.e. closed building conditions are not required if a test is more than 90 days).  Long-term test kits can be ordered from Alpha Energy Laboratories.

The Environmental Protection Agency (EPA), the Center for Disease Control (CDC), and the Nevada Radon Education Program  recommends that all citizens test their homes with a radon device that has been shown to be proficient, to protect their family's health. If high radon levels are found, a home should be remedied by a competent and proficient mitigation contractor. The EPA recommends that homes be tested with long-term tests, but in real estate transactions, taking a long-term test is often not possible or practical.

New Home Construction Codes and Regulations

Currently, there are no statewide regulations in Nevada that require radon-reducing construction. However, NREP encourages builders to voluntarily use radon-reducing construction in Zone 1 and Zone 2 areas within the state as shown on the Nevada EPA Map of Radon Zones. As radon and geology do not follow county lines an individual building a home may want to consider radon-reducing construction techniques wherever they are building. See Radon-Reducing New Construction.

Radon-reducing construction techniques are effective and cost-efficient steps to take during the initial construction of a home that significantly reduce the potential for high levels of radon. If incorporated at the time of construction, radon systems can be hidden and not visible in the finished home. If a buyer is considering the purchase of a lot on which to build, he or she may want to consider having the builder incorporate a passive radon-reducing system. A new home constructed with a passive system must still be tested after completion.

Continuing Education for the Real Estate Professional

Radon's classification as a cancer causing agent has led many home buyers, as well as financial institutions, to desire that radon be less than EPA's action level of 4.0 pCi/l. NREP offers free continuing education classes for Nevada realtors. Contact chrisk@unr.edu to schedule a class. 
For more information:
Chris Kelly
Email: ChrisK@unr.edu 
State of Nevada licensed continuing education instructor

See Measurement and Mitigation Training Centers links in the Resource section. Home inspectors, builders, or others may wish to augment their services by becoming certified through the American Association of Radon Technologists and Scientists-National Radon Proficiency Program (AARST-NRPP) and the National Radon Safety Board (NRSB). Courses include those for measurement, mitigation and new home construction.

Kelly, C. 2022, Testing for Real Estate Transactions, Extension | University of Nevada, Reno. IP

Learn more about the author(s)


Also of Interest:

Radon in Real Estate - Continuing Education Flyer
The Nevada Radon Education Program (NREP) offers a three-hour continuing education (CE) course that is offered at Realtor broker offices. Contact the Nevada Radon Education Program 775-336-0252.
Kelly, C. 2022, Extension | University of Nevada, Reno. IP
Washoe County-Reno area Radon Potential Map - 2018
Use this map to find out the potential of radon exposure in Washoe County-Reno/Sparks area homes.
Kelly, C. 2022, Extension | University of Nevada, Reno. IP
White Pine County Radon Map
This is the radon map of White Pine County in Nevada. This shows Radon potential based on data collected from completed radon tests from 1989-2018.
Kelly, Christine 2022, Extension | University of Nevada, Reno IP
How Radon Gas Enters Homes
Radon can enter and collect inside almost any home or other building through dirt floors, hollow block walls, cracks in the foundation floor and walls, sump pumps, openings around floor drains, joints and foundation openings for pipes, sewers and other utility connections.
Howe, S. 2019, Extension | University of Nevada, Reno. IP
Radon Gas Education
Flyer for radon education class for realtors.
Kelly, Chris 2024, University of Nevada Reno Extension

Associated Programs

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Nevada Radon Education Program

The Nevada Radon Education Program is funded through a grant from the EPA to educate Nevadans about the health risk posed by elevated levels of radon in the home. The Extension program offers literature, educational presentations and low-cost radon test kits in many county Extension and partner offices.