Home Buyer’s and Seller’s Guide to
The EPA recommends:
- If you are buying a
home or selling your home, have it tested for radon.
- For a new home, ask
if radon-resistant construction features were used and if the home has
- Fix the home if the
radon level is 4 picoCuries per liter (pCi/L) or higher.
- Radon levels less
than 4 pCi/L still pose a risk, and in many cases, may be reduced.
- Take steps to
prevent device interference when conducting a radon test.
The EPA estimates that radon
causes thousands of cancer deaths in the U.S. each year.
* Radon is
estimated to cause about 21,000 lung cancer deaths per year.
The numbers of deaths from other
causes are taken from the Centers for Disease Control and Prevention’s
1999-2001 National Center for Injury Prevention and Control Report and 2002
National Safety Council Reports.
Radon is a cancer-causing,
You cannot see, smell or taste
radon. But it still may be a problem in your home. When you breathe air
containing radon, you increase your risk of getting lung cancer. In fact,
the Surgeon General of the United States 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
You should test for radon.
Testing is the only way to find out your home’s radon levels.
The EPA and the Surgeon General recommend testing all homes below the third
floor for radon.
You can fix a radon problem.
If you find that you have high radon levels, there are ways to
fix a radon problem. Even very high levels can be reduced to acceptable levels.
If You Are Selling a Home…
The EPA recommends that you test your home before putting it on
the market and, if necessary, lower your radon levels. Save the test results
and all information you have about steps that were taken to fix any problems.
This could be a positive selling point.
If You Are Buying a Home…
The EPA recommends that you know
what the indoor radon level is in any home you are considering buying.
Ask the seller for their radon test results. If the home has a
radon-reduction system, ask the seller for information they have about the system.
If the home has not yet been
tested, you should have the house tested.
If you are having a new home built,
there are features that can be incorporated into your home during construction
to reduce radon levels.
These radon testing guidelines have
been developed specifically to deal with the time-sensitive nature of home
purchases and sales, and the potential for radon device interference.
These guidelines are slightly different from the guidelines in other EPA
publications which provide radon testing and reduction information for non-real
This guide recommends three short-term testing options for
real estate transactions. The EPA also recommends testing a home in the
lowest level which is currently suitable for occupancy, since a buyer may choose
to live in a lower area of the home than that used by the seller.
1. Why do you need
to test for radon?
a. Radon has been found
in homes all over the U.S.
Radon is a radioactive gas that has
been found in homes all over the United States. It comes from the natural
breakdown of uranium in soil, rock and water, and gets into the air you
breathe. Radon typically moves up through the ground to the air above, and into
your home through cracks and other holes in the foundation. Radon can also
enter your home through well water. Your home can trap radon inside.
Any home can have a radon problem,
including new and old homes, well-sealed and drafty homes, and homes with
or without basements. In fact, you and your family are most likely to get your
greatest radiation exposure at home. That is where you spend most of your time.
Nearly one out of every 15 homes in the United States is
estimated to have an elevated radon level (4 pCi/L or more). Elevated
levels of radon gas have been found in homes in your state.
b. The EPA and the Surgeon General
recommend that you test your home.
Testing is the only way to know if you and your family are at
risk from radon. The EPA and the Surgeon General recommend testing all homes
below the third floor for radon.
You cannot predict radon levels
based on state, local, or neighborhood radon measurements. Do not
rely on radon test results taken in other homes in the neighborhood to estimate
the radon level in your home. Homes which are next to each other can have
different radon levels. Testing is the only way to find out what your
home’s radon level is.
In some areas, companies may offer
different types of radon service agreements. Some agreements let you pay
a one-time fee that covers both testing and radon mitigation, if
“Indoor radon gas is the second-leading cause of lung
cancer in the United States, and breathing it over prolonged periods can
present a significant health risk to families all over the country. It’s
important to know that this threat is completely preventable. Radon can
be detected with a simple test, and fixed through well-established venting
2. I’m selling a home. What
should I do?
a. If your home has
already been tested for radon…
If you are thinking of selling your
home and you have already tested your home for radon, review the Radon
Testing Checklist to make sure that the test was done correctly.
If so, provide your test results to the buyer.
No matter what kind of test you
took, a potential buyer may ask for a new test, especially if:
the Radon Testing
Checklist items were not met;
the last test is
not recent, (e.g., within two years);
you have renovated
or altered your home since you tested; or
the buyer plans to
live in a lower level of the house than was tested, such as a basement suitable
for occupancy but not currently lived in.
A buyer may also ask for a new test if your state or local
government requires disclosure of radon information to buyers.
b. If your home has not yet been tested for radon…
Have a test taken as soon as
possible. If you can, test your home before putting it on the market. You
should test in the lowest level of the home which is suitable for occupancy.
This means testing in the lowest level that you currently live in or a lower
level not currently used, but which a buyer could use for living space without
The radon test result is important
information about your home’s radon level. Some states require radon
measurement testers to follow a specific testing protocol. If you do the
test yourself, you should carefully follow the testing protocol for your area
or the EPA’s Radon Testing Checklist. If you hire a contractor to test
your residence, protect yourself by hiring a qualified individual or company.
You can determine a service provider’s
qualifications to perform radon measurements or to mitigate your home in
several ways. Many states require radon professionals to be licensed,
certified or registered. Most states can provide you with a list of
knowledgeable radon service providers doing business in your state.
In states that don’t regulate radon services, ask the contractor if
they hold a professional proficiency or certification credential. Such
programs usually provide members with a photo-ID card which indicates their
qualification(s) and its expiration date. If in doubt, you should check
with their credentialing organization. Alternatively, ask the contractor
if they’ve successfully completed formal training appropriate for testing or
mitigation, e.g., a course in radon measurement or radon mitigation.
3. I’m buying a home. What
should I do?
a. If the home has already been tested for radon…
If you are
thinking of buying a home, you may decide to accept an earlier test result
from the seller, or ask the seller for a new test to be conducted by
a qualified radon tester. Before you accept the seller’s test,
you should determine the results of previous testing by finding out:
conducted the previous test (the homeowner, a radon professional, or some other
in the home the previous test was taken, especially if you may plan to live in
a lower level of the home. For example, the test may have been taken on
the first floor. However, if you want to use the basement as living
space, test there, too;
if any, structural changes, alterations, or changes in the heating,
ventilation, and air conditioning (HVAC) system have been made to the house
since the test was done. Such changes may affect radon levels.
If you accept the seller’s test,
make sure that the test followed the Radon Testing Checklist.
If you decide that a new test is needed, discuss it with the
seller as soon as possible.
b. If the home has not yet been tested for radon…
Make sure that a radon test is done as
soon as possible. Consider including provisions in the contract specifying:
the test will be located;
should conduct the test;
type of test to do;
to do the test;
the seller and the buyer will share the test results and test costs (if
radon mitigation measures will be taken, and who will pay for them.
Make sure that the test is done in the lowest level of the home suitable for
occupancy. This means the lowest level that you are going to use as living
space which is finished or does not require renovations prior to use. A state
or local radon official or qualified radon tester can help you make some of
these decisions. If you decide to finish or renovate an unfinished area of the
home in the future, a radon test should be taken before starting the project,
and after the project is finished. Generally, it is less expensive to install a
radon-reduction system before (or during) renovations rather than afterward.
4. I’m buying or
building a new home. How can I protect my family?
a. Why should I buy a radon-resistant
Radon-resistant techniques work. When installed properly
and completely, these simple and inexpensive passive techniques can help to
reduce radon levels. In addition, installing them at the time of
construction makes it easier to reduce radon levels further if the passive
techniques don’t reduce radon levels below 4 pCi/L. Radon-resistant
techniques may also help to lower moisture levels and those of other
soil-gases. Radon-resistant techniques:
make upgrading easy: Even if
are cost-effective: Building
save money: When installed properly
In a new home, the cost to install passive
radon-resistant features during construction is usually between $350 to
$500. In some areas, the cost may be as low as $100. A qualified
mitigator will charge about $300 to add a vent fan to a passive system, making
it an active system and further reducing radon levels. In an existing
home, it usually costs between $800 to $2,500 to install a radon
b. What are radon-resistant features?
Radon-resistant features may vary for different foundations and
site requirements. If you’re having a house built, you can learn about
the EPA’s Model Standards (and architectural drawings) and explain the
techniques to your builder. If your new house was built (or will be
built) to be radon-resistant, it will include these basic elements:
5. How can I get
reliable radon test results?
Radon testing is easy and the only way to find out if you have a
radon problem in your home.
a. Types of Radon Devices
Since you cannot see or smell
radon, special equipment is needed to detect it. When you’re ready to
test your home, you can order a radon test kit by mail from a qualified radon
measurement service provider or laboratory. You can also hire a qualified
radon tester, very often a home inspector, who will use the radon
device(s) suitable to your situation. If you hire a home inspector, make sure
you hire a qualified InterNACHI member — specifically, an IAC2
certified air-quality professional. The most common types of
radon testing devices are listed below.
Passive radon-testing devices do
not need power to function. These include charcoal canisters,
alpha-track detectors, charcoal liquid scintillation devices, and electret
ion chamber detectors, which are available in hardware, drugstores,
and other stores; they can also be ordered by mail or phone. These
devices are exposed to the air in the home for a specified period of time, and
then sent to a laboratory for analysis. Both short-term and long-term
passive devices are generally inexpensive. Some of these devices may have
features that offer more resistance to test interference or disturbance than
other passive devices. Qualified radon testers may use any of these devices to
measure the home’s radon level.
Active radon-testing devices require power to function. These
include continuous radon monitors and continuous working-level
monitors. They continuously measure and record the amount of
radon and its decay products in the air. Many of these devices provide
a report of this information, which can reveal any unusual or abnormal swings
in the radon level during the test period. A qualified tester can explain this
report to you. In addition, some of these devices are specifically
designed to deter and detect test interference. Some technically advanced
active devices offer anti-interference features. Although these tests may
cost more, they may ensure a more reliable result.
b. General Information for All
A state or local radon official can
explain the differences between devices, and recommend the ones which are most
appropriate for your needs and expected testing conditions.
Make sure to use a radon measurement
device from a qualified laboratory. Certain precautions should be
followed to avoid interference during the test period. See the Radon
Testing Checklist for more information on how to get a reliable test
Radon Test Device Placement
The EPA recommends that testing
device(s) be placed in the lowest level of the home suitable for occupancy.
This means testing in the lowest level (such as a basement) which a buyer could
use for living space without renovations. The test should be conducted in a
room to be used regularly (such as a family room, living room, play room,
den or bedroom); do not test in a kitchen, bathroom, laundry room or
hallway. Usually, the buyer decides where to locate the radon test, based
on their expected use of the home. A buyer and seller should explicitly
discuss and agree on the test location to avoid any misunderstanding.
Their decision should be clearly communicated to the person performing the
c. Preventing or Detecting Test
There is a potential for test
interference in real estate transactions. There are several ways to prevent or
detect test interference:
Use a test device
that frequently records radon or decay-product levels to detect unusual swings.
Employ a motion
detector to determine whether the test device has been moved or if testing
conditions have changed.
Use a proximity
detector to reveal the presence of people in the room, which may correlate to
possible changes in radon levels during the test.
barometric pressure to identify weather conditions which may have affected the
temperature to help assess whether doors and windows have been opened during
seals to windows to ensure closed-house conditions.
Have the seller/occupant
sign a non-interference agreement.
Home buyers and sellers should consult a qualified radon test
provider about the use of these precautions.
d. Length of Time to Test
There are two general ways to test
your home for radon:
Because radon levels vary from day to day and from season to
season, a short-term test is less likely than a long-term test to tell you your
year-round average radon level. However, if you need results quickly, a
short-term test may be used to decide whether to fix the home.
The quickest way to test is with short-term tests. Short-term
tests remain in your home from two days to 90 days, depending on the device.
There are two groups of devices which are more commonly used for short-term
testing. The passive-device group includes alpha-track detectors,
charcoal canisters, charcoal liquid scintillation detectors, and electret
ion chambers. The active device group consists of different types of
Whether you test
Long-term tests remain in your home for more than 90 days. Alpha-track andelectret ion chamber detectors are commonly used for this type of
testing. A long-term test will give you a reading that is more likely to tell
you your home’s year-round average radon level than a short-term test. If time
permits, long-term tests (more than 90 days) can be used to confirm initial
short-term results. When long-term test results are 4 pCi/L or higher, the EPA
recommends mitigating the home.
e. Doing a Short-Term Test…
If you are testing in a real estate transaction and you need
results quickly, any of the following three options for short-term tests
are acceptable in determining whether the home should be fixed. Any real estate
test for radon should include steps to prevent or detect interference with the
There are trade-offs among the
Short-Term Testing Options
What to Do Next
Take an initial short-term test for at least 48
Fix the home if the average of two tests is 4 pCi/L or more.
Fix the home if the average of the two tests is 4 pCi/L or
Fix the home if the average radon level is 4 pCi/L or more.
f. Using testing devices
properly for reliable results.
If you do the test yourself:
When you are taking a short-term
test, close windows and doors and keep them closed, except for normal entry and
exit. If you are taking a short-term test lasting less than four days, be
Close your windows
and outside doors at least 12 hours before beginning the test.
Do not conduct
short-term tests lasting less than four days during severe storms or periods of
Follow the testing
instructions and record the start time and date.
Place the test
device at least 20 inches above the floor in a location where it will not be
disturbed and where it will be away from drafts, high heat, high humidity, and
Leave the test kit
in place for as long as the test instructions say.
Once you have
finished the test, record the stop time and date, re-seal the package, and
return it immediately to the lab specified on the package for analysis.
You should receive your test results within a few weeks. If you
need results quickly, you should find out how long results will take and, if
necessary, request expedited service.
If you hire a qualified radon tester:
In many cases, home buyers and
sellers may decide to have the radon test done by a qualified radon tester who
knows the proper conditions, test devices, and guidelines for obtaining a
reliable radon test result. They can also:
- evaluate the home
and recommend a testing approach designed to make sure you get reliable
- explain how proper
conditions can be maintained during the radon test;
- emphasize to
occupants of a home that a reliable test result depends on their
cooperation. Interference with, or disturbance of, the test or
closed-house conditions will invalidate the test result;
- analyze the data
and report measurement results; and
- provide an
g. Interpreting Radon Test Results
The average indoor radon level is estimated to be about 1.3
pCi/L; roughly 0.4 pCi/L of radon is normally found in the outside air. The
U.S. Congress has set a long-term goal that indoor radon levels be no more than
outdoor levels. While this goal is not yet technologically achievable for all
homes, radon levels in many homes can be reduced to 2 pCi/L or
Radon Test Results Reported
in Two Ways
Your radon test
results may be reported in either picoCuries per liter of air (pCi/L) or
working levels (WL). If your test result is in pCi/L, the EPA recommends you
fix your home if your radon level is 4 pCi/L or higher. If the test result is
in WL, the EPA recommends you fix the home if the working level is 0.02 WL or
higher. Some states require WL results to be converted to pCi/L to
Sometimes, short-term tests are
less definitive about whether the home is at or above 4 pCi/L, particularly
when the results are close to 4 pCi/L. For example, if the average of two
short-term tests is 4.1 pCi/L, there is about a 50% chance that the year-round
average is somewhat below 4 pCi/L.
However, the EPA believes that any
radon exposure carries some risk; no level of radon is safe. Even radon levels
below 4 pCi/L pose some risk. You can reduce your risk of lung cancer by
lowering your radon level.
As with other environmental
pollutants, there is some uncertainty about the magnitude of radon health
risks. However, we know more about radon risks than risks from most other
cancer-causing substances. This is because estimates of radon risks are based on
data from human studies on underground miners. Additional studies on more
typical populations are underway.
Your radon measurement will give
you an idea of your risk of getting lung cancer from radon. Your chances of
getting lung cancer from radon depend mostly on:
- your home’s radon
- the amount of time
you spend in your home; and
- whether you are a
smoker or have ever smoked.
Smoking combined with radon is an
especially serious health risk. If you smoke or are a former smoker, the
presence of radon greatly increases your risk of lung cancer. If you stop
smoking now and lower the radon level in your house, you will reduce your lung
Based on information contained in the National Academy of
Sciences’ 1998 report, The Health Effects of Exposure to Indoor Radon,
your radon risk may be somewhat higher than shown, especially if you have never smoked.
It’s never too late to reduce your risk to lung cancer. Don’t wait to
test and fix a radon problem. If you are a smoker, stop smoking.
For reliable test results, follow this Radon Testing
Checklist carefully. Testing for radon is not complicated.
Improper testing may yield inaccurate results and require another test.
Disturbing or interfering with the test device or with closed-house conditions
may invalidate the test results, and is actually illegal in some
states. If the seller or qualified tester cannot confirm that all items
have been completed, take another test.
Before conducting a radon test:
the occupants of the importance of proper testing conditions. Give the
occupants written instructions or a copy of this Guide and explain the
the radon test for a minimum of 48 hours; some test devices have a minimum
exposure time greater than 48 hours.
doing a short-term test ranging from two to four days, it is
important to maintain closed-house conditions for at least 12 hours before the
beginning of the test and during the entire test period.
doing a short-term test ranging from four to seven days, the EPA
recommends that closed-house conditions be maintained.
you conduct the test yourself, use a qualified radon measurement device and
follow the laboratory’s instructions. Your state may be able to provide
you with a list of do-it-yourself test devices available from qualified
you hire someone to do the test, hire only a qualified individual. Some
states issue photo identification (ID) cards; ask to see it. The tester’s
ID number, if available, should be included or noted in the test report.
test should include method(s) to prevent or detect interference with testing
conditions, or with the testing device itself.
the house has an active radon-reduction system, make sure the vent fan is
operating properly. If the fan is not operating properly, have it (or ask
to have it) repaired and then test it.
mean keeping all windows closed, keeping doors closed except for normal entry
and exit, and not operating fans or other machines which bring in air from
outside. Fans that are part of a radon-reduction system or small exhaust
fans operating for only short periods of time may run during the test.
During a radon test:
closed-house conditions during the entire time of a short-term test, especially
for tests shorter than one week.
the home’s heating and cooling systems normally during the test. For tests
lasting less than one week, operate only air-conditioning units which
re-circulate interior air.
not disturb the test device at any time during the test.
a radon-reduction system is in place, make sure the system is working properly
and will be in operation during the entire radon test.
After a radon test:
you conduct the test yourself, be sure to promptly return the test device to
the laboratory. Be sure to complete the required information, including
start and stop times, test location, etc.
an elevated level is found, fix the home. Contact a qualified radon-reduction
contractor about lowering the radon level. The EPA recommends that you
fix the home when the radon level is 4 pCi/L or more.
sure that you or the radon tester can demonstrate or provide information to
ensure that the testing conditions were not violated during the testing period.
6. What should I do
if the radon level is high?
a. High radon levels can be reduced.
The EPA recommends that you take
action to reduce your home’s indoor radon levels if your radon test result is 4
pCi/L or higher. It is better to correct a radon problem before placing your
home on the market because then you will have more time to address a radon
If elevated levels are found during the real estate transaction,
the buyer and seller should discuss the timing and costs of the radon
reduction. The cost of making repairs to reduce radon levels depends on
how your home was built and other factors. Most homes can be fixed for about
the same cost as other common home repairs, such as painting or
having a new hot water heater installed. The average cost for a contractor to
lower radon levels in a home can range from $800 to about $2,500.
b. How to Lower The Radon Level in
A variety of methods can be used to
reduce radon in homes. Sealing cracks and other openings in the foundation is a
basic part of most approaches to radon reduction. The EPA does not recommend
the use of sealing alone to limit radon entry. Sealing alone has not
been shown to lower radon levels significantly or consistently.
In most cases, a system with a vent pipe and fan is used
to reduce radon. These “sub-slab depressurization” systems do
not require major changes to your home. Similar systems can also be installed
in homes with crawlspaces. These systems prevent radon gas from entering
the home from below the concrete floor and from outside the foundation.
Radon mitigation contractors may use other methods that may also work in your
home. The right system depends on the design of your home and other
Radon and Home Renovations
If you are planning any
major renovations, such as converting an unfinished basement area into living
space, it is especially important to test the area for radon before you begin.
If your test results indicate an
elevated radon level, radon-resistant techniques can be inexpensively included
as part of the renovation. Major renovations can change the level of radon in
any home. Test again after the work is completed.
You should also test your home again after it is fixed to be
sure that radon levels have been reduced. If your living patterns change and
you begin occupying a lower level of your home (such as a basement) you should
re-test your home on that level. In addition, it is a good idea to re-test your
home sometime in the future to be sure radon levels remain low.
c. Selecting a
Radon-Reduction (Mitigation) Contractor
Select a qualified radon-reduction
contractor to reduce the radon levels in your home. Any mitigation measures
taken or system installed in your home must conform to your state’s
The EPA recommends that the mitigation contractor review the
radon measurement results before beginning any radon-reduction work. Test
again after the radon mitigation work has been completed to confirm that
previous elevated levels have been reduced.
d. What can a qualified
radon-reduction contractor do for you?
A qualified radon-reduction
(mitigation) contractor should be able to:
- review testing
guidelines and measurement results, and determine if additional measurements
- evaluate the radon
problem, and provide you with a detailed, written proposal on how radon levels
will be lowered;
- design a
- install the system
according to EPA standards, or state or local codes; and
- make sure the
finished system effectively reduces radon levels to acceptable levels.
Choose a radon-mitigation
contractor to fix your radon problem just as you would for any other home
repair. You may want to get more than one estimate. Ask for and
check their references. Make sure the person you hire is qualified to install
a mitigation system. Some states regulate or certify radon-mitigation
Be aware that a potential conflict of interest exists if the
same person or firm performs the testing and installs the mitigation
system. Some states may require the homeowner to sign a waiver, in such
cases. Contact your state radon office for more information.
e. Radon in Water
The radon in your home’s indoor air
can come from two sources: the soil and your water supply.
Compared to radon entering your home through water, radon entering your home
through soil is a much larger risk. If you’ve tested for radon in air and
have elevated radon levels, and your water comes from a private well, have your
water tested. The devices and procedures for testing your home’s water
supply are different from those used for measuring radon in air.
The radon in your water supply
poses an inhalation risk and an ingestion risk. Research has shown that
your risk of lung cancer from breathing radon in the air is much larger than
your risk of stomach cancer from swallowing water with radon in it. Most
of your risk from radon in water comes from radon released into the air when
water is used for showering and other household purposes.
Radon in your home’s water is not
usually a problem when its source is surface water. Radon in water is
more likely when its source is ground water, e.g., a private well or a public
water supply system that uses ground water. Some public water systems
treat their water to reduce radon levels before it is delivered to your
home. If you are concerned that radon may be entering your home through
the water, and your water comes from a public water supply, contact your water
If you’ve tested your private well
and have radon in your water supply, it can be treated in one of two
ways. Point-of-entry treatment can effectively remove radon from the
water before it enters your home. Point-of-entry treatment usually
employs either granular activated-carbon (GAC) filters, or aeration
devices. While GAC filters usually cost less than aeration devices,
filters can collect radioactivity and may require a special method of
disposal. Point-of-use treatment devices remove radon from your water at
the tap, but only treat a small portion of the water you use, e.g., the water
you drink. Point-of-use devices are not effective in reducing the
risk of breathing radon released into the air from all water used in the