oEPA	EPA 402/K-10/005 | 2016 | www.epa.gov/radon
United States
Environmental Protection
Agency
Consumer's Guide
to Radon Reduction
How to Fix Your Home
Indoor Air Quality (IAQ)

-------
OVERVIEW
Red uce Radon Levels h Your Home
Radon is the leading cause of lung cancer for non-smokers and the
second leading cause of lung cancer for the general population. The
Surgeon General and EPA recommend testing for radon and reducing
radon in homes that have high levels. Fix your home if your radon level
is confirmed to be 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.
If you smoke and your home has high radon levels, your risk of lung
cancer is especially high.
Select a State Certified and/or Qualified Radon Mitigation
Contractor
Choose a qualified radon mitigation contractor to fix your home. Start by
checking with your state radon office. Many states require radon
professionals to be licensed, certified, or registered. You also can contact
private radon proficiency programs for lists of privately certified radon
professionals in your area. See pages 4 and 17 for more information.
Radon Reduction Techniques Work
Radon reduction systems work. Some radon reduction systems can
reduce radon levels in your home by up to 99 percent. Most homes can
be fixed for about the same cost as other common home repairs. Your
costs may vary depending on the size and design of your home and
which radon reduction methods are needed. Get an estimate from one or
more qualified radon mitigation contractors. Hundreds of thousands of
people have reduced radon levels in their homes.
Maintain Your Radon Reduction System
Maintaining your radon reduction system takes little effort and keeps the
system working properly and radon levels low. See page 13 for more
information.
AConsumer'sGuideto Radon Reduction

-------
INTRODUCTION
This booklet is for people who tested their home for radon and
have elevated radon levels — 4 pCi/L or higher. This booklet can
help you:
¦	Select a qualified radon mitigation contractor to reduce the radon
levels in your home.
¦	Determine an appropriate radon reduction method.
¦	Maintain your radon reduction system.
Your state radon office can provide information on how to test your home or how
to locate a qualified radon professional https://www.epa.gov/radon/find-
infonnation-about-local-radon-zones-and-state-contact-infonnation. EPA's A
Citizen's Guide to Radon and The Home Buyer's and Seller's Guide to Radon
have information on radon testing. Both documents are available at
https://www.epa.gov/radon/publications-about-radon.
www.epa.gov/radon 3

-------
HOW RADON ENTERS YOURHOME
Radon is a naturally occurring
radioactive gas produced by the
breakdown of uranium in soil, rock,
and water. Air pressure inside your home is
usually lower than pressure in the soil
around your home's foundation. Because of
this difference in pressure, your home acts
like a vacuum, drawing radon in through
foundation cracks and other openings.
Radon also may be present in well water
and can be released into the air in your
home when water is used for showering and
other household uses. In most cases, radon
entering the home through water is a small
risk compared with radon entering your
home from the soil. In a small number of
homes, the building materials — such as
granite and certain concrete products
— can give off radon, although building materials rarely cause radon problems by
themselves. In the United States, radon gas in soils is the principal source of
elevated radon levels in homes.
RADON IS A CANCER-CAUSING,
RADIOACTIVE GAS
Radon is estimated to cause tens of thousands of lung cancer deaths each
year. In fact, the Surgeon General has warned that radon is the second
leading cause of lung cancer in the United States. Only smoking causes
more lung cancer deaths. If you smoke and your home has high radon levels,
your risk of lung cancer is especially high.
WHAT DO YOUR RADON TEST RESULTS MEAN?
Any radon exposure has some risk of causing lung cancer. The lower the
radon level in your home, the lower your family's risk of lung cancer.
LTlic amount of radon in the air is measured in pCi/L.
2
AConsumer'sGuideto Radon Reduction

-------
The U.S. Congress has set a long-term
goal that indoor radon levels be no
more than outdoor levels; about 0.4
pCi/L of radon is normally found in the
outside air. EPA recommends fixing
your home if the results of one long-
term test or the average of two short-
term tests show radon levels of 4 pCi/L
or higher. With today's technology,
radon levels in most homes can be
reduced to 2 pCi/L or below. You also
may want to consider fixing if the level
is between 2 and 4 pCi/L.
A short-term test remains in your home
for two days to 90 days, whereas a
long-term test remains in your home
for more than 90 days. All radon tests
should be taken for a minimum of
48 hours. A short-term test will yield
faster results, but a long-term test will
give you a better understanding of
your home's year-round average radon
level.
EPA recommends two categories of
radon testing. One category is for
concerned homeowners or occupants
whose home is not for sale; refer to
EPA's pamphlet "A Citizen's Guide
to Radon" for testing guidance. The
second category is for real estate
transactions; refer to EPA's pamphlet
"Home Buyer's and Seller's Guide to
Radon," which provides guidance and
answers to some common questions.
Both documents are available at https://
epa.gov/radon/publications-about-radon.
SELECTING A RADON
TEST KIT
Since you cannot see or smell radon,
special equipment is needed to detect
it. When you're ready to test your
home, contact your state radon office
for information on locating qualified
test kits or qualified radon testers. You
also can order test kits and obtain
information at http://sosradon.org/
There are two types of radon testing
devices. 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. Both short- and long-term
passive devices are generally
inexpensive. Active radon testing
devices require power to function and
usually provide hourly readings and an
average result for the test period. These
include continuous radon monitors and
continuous working level monitors, and
these tests may cost more. A state or
local official can explain the differences
between the devices and recommend
ones that are most appropriate for your
needs and expected testing conditions.
Make sure to use a radon testing device
from a qualified laboratory.
www.epa.gov/radon 3

-------
WHY HIRE A CONTRACTOR?
EPA recommends that you have a qualified radon mitigation contractor fix
your home because lowering high radon levels requires specific technical
knowledge and special skills. Without the proper equipment or technical
knowledge, you could actually increase your radon level or create other potential
hazards and additional costs. However, if you decide to do the work yourself, get
information on appropriate training courses from your state radon office.
WILL ANY CONTRACTOR DO?
EPA recommends that you use a certified or qualified radon mitigation
contractor trained to fix radon problems. You can determine a service
provider's qualifications to perform radon measurements or to mitigate your
home in several ways. First, check with your state radon office. Many states
require radon professionals to be licensed, certified or registered, and to install
radon mitigation systems that meet state requirements. Most states can provide
you with a list of knowledgeable radon service providers doing business in the
state (https://www.epa.gov/radon/find-information-about-local-radon-zones-and-
state-contact-infonnation).
In states that don't regulate radon services, ask the contractor if they hold a
professional proficiency or certification credential, and if they follow industry
consensus standards, such as the American Society for Testing and Materials,
ASTM, Standard Practice for Installing Radon Mitigation Systems in Existing
Low-Rise Residential Buildings, E2121. You can contact private proficiency
programs for lists of privately certified professionals in your area. Such
programs usually provide members with a photo ID card, which indicates their
qualifications and the ID card's expiration date. For more information on private
proficiency programs, visit https://www.epa.gov/radon/find-radon-test-kit-or-
measurement-and-mitigation-professional#what, or contact your state radon
office.
HOWTOSELECTACONTRACTOR
Get Estimates
Choose a contractor to fix a radon problem just as you would choose someone
to do other home repairs. It is wise to get more than one estimate, to ask for
references, and to contact some of those references to ask if they are satisfied
with the contractor's work. Also, ask your state radon office or your county or
state consumer protection office for information about the contractors.
¦
AConsumer'sGuideto Radon Reduction

-------
Use this checklist when evaluating and comparing contractors and ask the
following questions:
YES NO
EH ~ Will the contractor provide references or photographs, as well as test results
of before and after radon levels of past radon reduction work?
EH EH Can the contractor explain what the work will involve, how long it will take
to complete, and exactly how the radon reduction system will work?
EH EH Does the contractor charge a fee for any diagnostic tests? Although many
contractors give free estimates, they may charge for diagnostic tests. These
tests help determine what type of radon reduction system should be used and
in some cases are necessary, especially if the contractor is unfamiliar with the
type of house structure or the anticipated degree of difficulty. See "Radon
Reduction Techniques" on page 8 for more on diagnostic tests.
EH EH Did the contractor inspect your home's structure before giving you an
estimate?
EH EH Did the contractor review the quality of your radon measurement results and
determine if appropriate testing procedures were followed?
Compare the contractor's proposed costs and consider what you get for your
money, taking into account: a less expensive system may cost more to operate
and maintain; a less expensive system may have less aesthetic appeal; a more
expensive system may be best for your home; and, the quality of the building
material will affect how long the system lasts.
Do the contractors" proposals and estimates include:
YES NO
~ ~
~	~
~	~
~	~
~	~
~	~
www.epa.gov/radon 5
Proof of state certification, professional proficiency or certification
credentials?
Proof of liability insurance and being bonded, and having all necessary
licenses to satisfy local requirements?
Diagnostic testing prior to design and installation of a radon reduction
system?
Installation of a warning device to caution you if the radon reduction system
is not working correctly?
Testing after installation to make sure the radon reduction system works
well?
A guarantee to reduce radon levels to 4 pCi/L or below? And if so, for how
long?

-------
The Contract
Ask the contractor to prepare a contract before any work starts. Read the contract
before you sign it. Make sure everything in the contract matches the original
proposal. The contract should describe exactly what work will be done prior to
and during the installation of the
system, what the system consists
of, and how the system will
operate. Many contractors provide
a guarantee that they will adjust
or modify the system to reach
a negotiated radon level (e.g., 2
pCi/L or less). Carefully read the
conditions of the contract describing
the guarantee. Consider optional
additions to your contract that
may add to the initial cost of the system, but may be worth the extra expense.
Typical options might include an extended warranty, a service plan or improved
aesthetics.
Important information that should appear in the contract includes:
EH The total cost of the job, including all taxes and permit fees; how
much, if any, is required for a deposit; and when payment is due in
full.
EH The time needed to complete the work.
EH An agreement by the contractor to obtain necessary permits and
follow required building codes.
EH A statement that the contractor carries liability insurance and is
bonded and insured to protect you in case of injury to persons, or
damage to property, while the work is being done.
EH A guarantee that the contractor will be responsible for damage during
the job and cleanup after the job.
EH Details of any guarantee to reduce radon below a negotiated level.
EH Details of warranties or other optional features associated with the
hardware components of the mitigation system.
EH A declaration stating whether any warranties or guarantees are
transferable if you sell your home.
EH A description of what the contractor expects the homeowner to do,
such as make the work area accessible, before work begins.
fCOMTRAC
BftrfriK)6
B'wuNiwfi
VDevicsx j
6
AConsumer'sGuideto Radon Reduction

-------
WHAT TO LOOK FOR IN A RADON
REDUCTION SYSTEM
In selecting a radon reduction method for your home, you and your contractor
should consider several things, including: how high your initial radon level
is, the costs of installation and system operation, your home size, and your
foundation type.
Installation and
Operating Costs
Most types of radon reduction systems
cause some loss of heated or air
conditioned air, which could increase
your utility bills. I low much your
utility bills increase will depend on
the climate you live in, what kind of
reduction system you select, and how
your home is built. Systems that use
fans are more effective in reducing
radon levels; however, they will
slightly increase your electric bill.
www.epa.gov/radori 7

-------
RADON REDUCTION TECHNIQUES
Any information that you may have about
the construction of your home could help
your contractor choose the best system. Your
contractor will perform a visual inspection of your home and design a system
that considers specific features of your home. If this inspection fails to provide
enough information, the contractor may need to perform diagnostic tests during
the initial phase of the installation to help develop the best radon reduction
system for your home. For instance, your contractor can use chemical smoke to
find the source and direction of air movement. A contractor can learn air flow
sources and directions by watching a small amount of smoke that he or she shot
into holes, drains, sumps or along cracks. The sources of air flow show possible
radon routes. A contractor may have concerns about backdrafting of combustion
appliances when considering radon mitigation options, and may recommend that
the homeowner have the appliances checked by a qualified inspector.
There are several methods a contractor
can use to lower radon levels in your
home. Some techniques prevent radon
from entering your home while others
reduce radon levels after it has entered. EPA
generally recommends methods that prevent
the entry of radon. Soil suction, for example,
prevents radon from entering your home by
drawing the radon from below the home and
venting it through a pipe, or pipes, to the air
above the home where it is quickly diluted.
Another type of diagnostic test is a soil communication test. This test uses a
vacuum cleaner and chemical smoke to determine how easily air can move from
one point to another under the foundation. By inserting a vacuum cleaner hose
in one small hole and using chemical smoke in a second small hole, a contractor
can see if the smoke is pulled down into the second hole by the force of the
vacuum cleaner's suction. Watching the smoke during a soil communication test
helps a contractor decide if certain radon reduction systems would work well in
your home.
Whether diagnostic tests are needed is decided by details specific to your home,
such as the foundation design, what kind of material is under your home, and by
the contractor's experience with similar homes and similar radon test results.
8
AConsumer'sGuideto Radon Reduction

-------
Home Foundation Types
Your home type will affect the kind of radon reduction system that will work
best. Homes are generally categorized according to their foundation design
For example: basement; slab-on-grade, concrete poured at ground level; or
crawlspace, a shallow unfinished space under the first floor. Some homes have
more than one foundation design feature. For instance, it is common to have
a basement under part of the home and to have a slab-on-grade or crawlspace
under the rest of the home. In these situations, a combination of radon reduction
techniques may be needed to reduce radon levels to below 4 pCi/L.
BASEMENT
*LAB-ON-G*?AD£ CRAWLSPACE
Radon reduction systems can be grouped by home foundation design. Find your
type of foundation design above and read about which radon reduction systems
may be best for your home.
Basement and Slab-on-Grade Homes
In homes that have a basement or a slab-on-grade foundation, radon is usually
reduced by one of four types of soil suction: subslab suction, drain-tile suction,
sump-hole suction, or block-wall suction.

Active subslab suction — also called
subslab depressurization — is the most
common and usually the most reliable
radon reduction method. One or more
suction pipes are inserted through the
floor slab into the crushed rock or soil
underneath. They also may be inserted
below the concrete slab from outside the
home. The number and location of suction
pipes that are needed depends on how
easily air can move in the crushed rock
or soil under the slab and on the strength
of the radon source. Often, only a single
suction point is needed.
www.epa.gov/radori 9

-------
A contractor usually gets this information from visual inspection, from diagnostic
tests or from experience. A radon vent fan connected to the suction pipes draws
the radon gas from below the home and releases it into the outdoor air while
simultaneously creating a negative pressure or vacuum beneath the slab. Common
fan locations include unconditioned home and garage spaces, including attics and
the exterior of the home.
Passive subslab suction is the same as active subslab suction except it relies on
natural pressure differentials and air currents instead of a fan to draw radon up
from below the home. Passive subslab suction is usually associated with radon-
resistant features installed in newly constructed homes. Passive subslab suction
is generally not as effective in reducing high radon levels as active subslab
suction.
Some homes have drain tiles or perforated pipe to direct water away from
the foundation of the home. Suction on these tiles or pipes is often effective in
reducing radon levels.
One variation of subslab and drain tile suction is sump-hole suction. Often, when
a home with a basement has a sump pump to remove unwanted water, the sump
can be capped so that it can continue to drain water and serve as the location for a
radon suction pipe.
Block-wall suction can be used in basement homes with hollow block foundation
walls. This method removes radon and depressurizes the block wall, similar to
subslab suction. This method is often used in combination with subslab suction.
Crawlspace Homes
An effective method to reduce radon levels in crawlspace 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 crawlspace homes. Another
less-favorable option is active crawlspace depressurization, which involves
drawing air directly from the crawlspace using a fan. This technique generally
does not work as well as submembrane suction and requires special attention to
combustion appliance backdrafting and sealing the crawlspace from other portions
of the home. It also may result in increased energy costs due to loss of conditioned
air from the home.
In some cases, radon levels can be lowered by ventilating the crawlspace
passively, or actively, with the use of a fan. Crawlspace ventilation may lower
indoor radon levels both by reducing the home's suction on the soil and by
diluting the radon beneath the home. Passive ventilation in a crawlspace is
10 AConsumer'sGuideto Radon Reduction

-------
achieved by opening vents or installing additional vents. Active ventilation
uses a fan to blow air through the crawlspace instead of relying on natural air
circulation. In colder climates, for either passive or active crawlspace ventilation,
water pipes, sewer lines and appliances in the crawlspace may need to be
insulated against the cold. These ventilation options could result in increased
energy costs for the home.
Other Types of Radon Reduction Methods
Other radon reduction techniques that can be used in any type of home include:
sealing, house or room pressurization, heat recovery ventilation and natural
ventilation.
Sealing cracks and other openings in the foundation is a basic part of most
approaches to radon reduction. Sealing the cracks limits the flow of radon into
your home, thereby making other radon reduction techniques more effective
and cost-efficient. It also reduces the loss of conditioned air. EPA does not
recommend the use of sealing alone to reduce radon because, by itself, sealing
has not been shown to lower radon levels significantly or consistently. It is
difficult to identify and permanently seal the places where radon is entering.
Normal settling of your home opens new entry routes and reopens old ones.
House or room pressurization uses a fan to blow air into the basement, or
living area from either upstairs or outdoors. It attempts to create enough pressure
at the lowest level indoors — in a basement, for example — to prevent radon
from entering into the home. The effectiveness of this technique is limited by
home construction, climate, other appliances in the home and occupant lifestyle.
In order to maintain enough pressure to keep radon out, the doors and windows
at the lowest level must not be left opened, except for normal entry and exit. This
approach generally results in more outdoor air being introduced into the home,
which can cause moisture intrusion and energy penalties. Consequently, this
technique should only be considered after the other, more-common techniques
have not sufficiently reduced radon.
A heat recovery ventilator, or HRV, also called an air-to-air heat exchanger,
can be installed to increase ventilation, which will help reduce the radon levels in
your home. An HRV will increase ventilation by introducing outdoor air while
using the heated or cooled air being exhausted to warm or cool the incoming air.
HRVs can be designed to ventilate all or part of your home, although they are
more effective in reducing radon levels when used to ventilate only the basement.
If properly balanced and maintained, they ensure a constant degree of ventilation
throughout the year. HRVs also can improve air quality in homes that have other
indoor pollutants. There could be significant increase in the heating and cooling
costs with an HRV, but not as great as ventilation without heat recovery.
www.epa.gov/radon 11

-------
Some natural ventilation occurs in all homes. By opening windows, doors
and vents on the lower floors, you increase the ventilation in your home. This
increase in ventilation mixes outdoor air with the indoor air containing radon,
and can result in reduced radon levels. However, once windows, doors and vents
are closed, radon concentrations most often return to previous values within
about 12 hours. Natural ventilation in any type of home should normally be
regarded as only a temporary radon reduction approach because of the following
disadvantages: loss of conditioned air and related discomfort; greatly increased
costs of conditioning additional outside air; and security concerns.
CHECKING YOUR CONTRACTOR'S WORK
Below is a list of basic installation requirements that your contractor
should meet when installing a radon reduction system in your home. It is
important to verify with your contractor that the radon mitigation standards
(ASTM E2121 in particular) are properly met to ensure that your radon reduction
system will be effective. You also can check with your state radon office to see if
there are state requirements that your contractor must meet.
EH Radon reduction systems must be clearly labeled. This will avoid accidental
changes to the system that could disrupt its function.
EH The exhaust pipes of soil suction systems must vent above the surface of the
roof and 10 feet or more above the ground, and must be at least 10 feet away
from windows, doors or other openings that could allow radon to reenter the
home, if the exhaust pipes do not vent at least 2 feet above these openings.
EH The exhaust fan must not be located in or below a livable area. For instance, it
should be installed in unconditioned space.
EH If installing an exhaust fan outside, the contractor must install a fan that meets
local building codes for exterior use.
EH Electrical connections of all active radon reduction systems must be installed
according to local electrical codes.
~ A warning device must be installed to alert you if an active system stops
working properly. Examples of system failure warning devices are: a liquid
gauge, a sound alarm, a light indicator, and a dial, or needle display, gauge.
The warning device must be placed where it can be seen or heard easily. Your
contractor should check that the warning device works. Later on, if your
monitor shows that the system is not working properly, call a contractor to
have it checked.
12 AConsumer'sGuideto Radon Reduction

-------
EH A post-mitigation radon test should be done within 30 days of system
installation, but no sooner than 24 hours after your system is in operation
with the fan on, if it has one. The contractor may perform a post-mitigation
test to check his work and the initial effectiveness of the system; however, it is
recommend that you also get an independent follow-up radon measurement.
Having an independent tester perform the test, or conducting the measurement
yourself, will eliminate any potential conflict of interest. To test the system's
effectiveness, a two- to seven-day measurement is recommended. Test
conditions: windows and doors must be closed 12 hours before and during the
test, except for normal entry and exit.
EH Make sure your contractor completely explains your radon reduction system,
demonstrates how it operates and explains how to maintain it. Ask for written
operating and maintenance instructions and copies of any warranties.
LIVING IN A HOME WITH A RADON
REDUCTION SYSTEM
Maintaining Your Radon Reduction System
Similar to a furnace or chimney, radon reduction systems need occasional
maintenance. If you have a fan powered (or active) system, you should look
at your warning device, usually a manometer, on a regular basis to make
sure the system is working correctly. Fans may last for five years or more —
manufacturer warranties tend not to exceed five years — and may then need to
be repaired or replaced. The cost to replace a fan varies as it is based on labor
and materials. Ask qualified mitigators for estimates before work begins. It is
a good idea to retest your home at least every two years to be sure radon levels
remain low.
Remember, the fan should NEVER be turned off; it must run continuously for
the system to work correctly.
The filter in an HRV requires periodic cleaning and should be changed twice a
year. Replacement filters for an HRV are easily changed and are priced between
$10 and $25. Ask your contractor where filters can be purchased. Also, the
vent that brings fresh air in from the outside needs to be inspected for leaves
and debris. The ventilator should be checked annually by a heating, ventilating
and air conditioning professional to make sure the air flow remains properly
balanced. HRVs used for radon control should run all the time.
www.epa.gov/radon 13

-------
Remodeling Your Home after Radon Levels
Have Been Lowered
If you decide to make major structural changes to your home after you have had
a radon reduction system installed, such as converting an unfinished basement
area into living space, ask your radon contractor whether these changes could
void any warranties. If you are planning to add a new foundation for an addition
to your home, ask your radon contractor what measures should be taken to
ensure reduced radon levels throughout the home. After you remodel, retest
in the lowest lived-in area to make sure the construction did not reduce the
effectiveness of the radon reduction system.
11

BUYING OR SELLING A HOME?
If you are buying or selling a home and
need to make decisions about radon, consult
EPA's "Home Buyer's and Seller's Guide
to Radon." If you are selling a home that
has a radon reduction system, inform
potential buyers and supply them with
information about your system's operation and
maintenance. If you are building a new home, consider
that it is almost always less expensive to build radon-resistant features into new
construction than it is to fix an existing home that has high radon levels. Ask
your builder if he or she uses radon-resistant construction features. Your builder
can refer to EPA's document "Building Radon Out: A Step-by-Step Guide On
How To Build Radon-Resistant Homes,"
(https://www.epa.gov/radon/publications-about-radon) or your builder can work
with a qualified contractor to design and install the proper radon reduction
system. To find a qualified contractor contact your state radon office.
All homes should be tested for radon and elevated radon levels should be
reduced. Even new homes built with radon-resistant features should be
tested after occupancy to ensure that radon levels are below 4 pCi/L. If you
have a test result of 4 pCi/L or more, you can have a qualified mitigator add a
vent fan to an existing passive system to further reduce the radon level in your
home.
14 AConsumer'sGuideto Radon Reduction

-------
RADON IN WATER
Most often, the radon in your home's indoor air can come from two sources,
the soil or your water supply. Compared to radon entering your home
through water, radon entering your home through soil is usually a much
larger risk. If you are concerned about radon and you have a private well, consider
testing for radon in both air and water. By testing for radon in both air and water,
the results could enable you to more completely assess the radon mitigation
options best suited to your situation. 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 a small ingestion risk.
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. Research has shown
that your risk of lung cancer from breathing radon in air is much larger than your
risk of stomach cancer from swallowing water with radon in it.
Radon in your home's water in not usually a problem when its source is surface
water. A radon in water problem is more likely when its source is ground water, such
as 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 supplier.
If you've tested your private well and have a radon in water problem, it can
be easily fixed. Your home's water supply can be treated in one of two ways;
point-of-use or point-of-entry. Point-of-entry treatment for the whole home can
effectively remove radon from the water before it enters your home's water
distribution system. Point-of-entry treatment usually employs either granular
activated carbon, or GAC, filters or aeration systems. While GAC filters usually
cost less than aeration systems, filters can collect radioactivity and may require a
special method of disposal. Both GAC filters and aeration systems have advantages
and disadvantages that should be discussed with your state radon office or a water
treatment professional. Point-of-use treatment devices remove radon from your
water at the tap, but only treat a small portion of the water you use, such as the
water you drink. Point-of-use devices are not effective in reducing the risk from
breathing radon released into the air from all water used in the home.
For information on radon in water, testing and treatment, and radon in drinking
water standards, or for general help, contact your state radon office
https://www.epa.gov/radon/find-information-about-local-radon-zones-and-state-
contact-infonnation.
www.epa.gov/radon 15

-------
RADON REDUCTION OF VARIOUS
MITIGATION TECHNIQUES
Technique
Typical Radon
Reduction
Comments
Subslab Suction
(Subslab
depressurization)
50 to 99 percent
Works best if air can move easily in material under slab.
Passive Subslab Suction
30 to 70 percent
May be more effective in cold climates; not as effective as
active subslab suction.
drain tile Suction
50 to 99 percent
Can work with either partial or complete drain tile loops.
Block-wall Suction
50 to 99 percent
Only in homes with hollow block-walls; requires sealing of
major openings.
Sump-Hole Suction
50 to 99 percent
Works best if air moves easily to sump from under the slab.
Submembrane
depresserizationina
Crawlspace
50 to 99 percent
Less heat loss than natural ventilation in cold winter climates.
natural ventilation in a
Crawlspace
0 to 50 percent
Costs variable.
Sealing of Radon Entry
Routes
See Comments
Normally only used with other techniques; proper materials and
installation required.
House (Basement)
Pressurization
50 to 99 percent
Works best with tight basement isolated from outdoors and
upperfloors.
natural ventilation
Variable/Temporary
Significant heated or cooled air loss; operating costs depend on
utility rates and amount of ventilation.
Heat Recovery
ventilation (HRv)
Variable/ See
comments
Limited use; effectiveness limited by radon concentration or
the amount of ventilation air available for dilution by the
HRV. Best Applied in limited-space areas like basements.
Private well water
Systems: Aeration
95 to 99 percent
Generally more efficient than GAC; requires annual cleaning to
maintain effectiveness and to prevent contamination; requires
venting radon to outdoors.
Private well water
Systems: Granular
Activated Carbon, or GAC
85 to 95 percent
Less efficient for higher levels than aeration; use for moderate
levels, around 5,000 pCi/L or less in water: radioactive radon
by-products can build on carbon; may need radiation shield
around tank and care in disposal.
Note: Mitigation costs vary due to technique, materials, and the extent of the problem. Typically the cost of radon mitigations are comparable
to other common home repairs.
16 A Consumer's Guide to Radon Reduction

-------
FOR FURTHER INFORMATION
EPA Radon Web site
https://www.epa.gov/radon
EPA's main radon home page. Includes links
to publications, hotlines, private proficiency
programs and more.
EPA Regional Offices
https://www.epa.gov/radon/find-
information-about-local-radon-zones-and-
state-contact-information. Check this Web
site for a listing of your EPA regional office.
EPA Publications
Most EPA radon publications are available
online at
https://www.epa.gov/radon/publications-
about-radon.
Hotlines
1-800-SOS-RADON (767-7236)
Operated by Kansas State University in
partnership with EPA. Order radon test kits by
phone.
1-800-426-4791
Safe Drinking Water Hotline, privately
operated under contract to EPA. For general
information on drinking water, radon in water,
testing and treatment and radon drinking
water standards.
Proficiency Programs
National Radon Proficiency Program (NRPP)
1-800-269-4174
www.aarst-nrpp.com/wp/
National Radon Safety Board (NRSB)
1-866-329-3474
www.nrsb.org
www.epa.gov/radon 17

-------
U.S. SURGEON GENERAL HEALTH ADVISORY
"Indoor radon 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 techniques." January 2005
https://www.epa.gov/radon/radon/consumers-guide-radon-
reduction-how-fix-your-home

-------