Radon Control in New Home Construction: Developments in State Policy
Background
According to the U.S. Environmental Protection Agency (EPA), indoor radon is the second leading cause of lung cancer in the United States and the leading cause of lung cancer among non-smokers. Lung cancer due to radon exposure is responsible for over 20,000 deaths in the U.S. each year. See http://www.epa.gov/radon/healthrisks.html.
Radon is a radioactive gas found in soil and rock in all parts of the United States. The concentration of radon in indoor air is affected by the way we design and construct houses and other buildings. EPA has established an “action level” of 4 picoCuries/liter (pCi/L) — the level at which a building owner should take action to reduce radon in the indoor air.
The EPA Map of Radon Zones shows the radon potential for each county in the nation. Zone 1 counties have the highest potential radon levels, with predicted average indoor radon screening levels greater than 4 pCi/L, while predicted average radon levels are 2-4 pCi/L in Zone 2 counties, and under 2 pCi/L in Zone 3 counties. See http://www.epa.gov/radon/zonemap.html. Although the map shows predicted average radon levels, high radon levels can be found in any area. The only way to know the radon level in a particular home is to test the home for radon.
When a new home is built, radon control techniques (also referred to as radon-resistant new construction) can be used to help keep radon from entering the home. The EPA has developed a voluntary guidance document on radon control techniques for new construction. The guidance recommends and describes the installation of a “passive sub-slab or sub-membrane depressurization system.” See U.S. EPA, Building Radon Out: A Step-by-Step Guide on How to Build Radon-Resistant Homes (2001), available at: http://www.epa.gov/radon/pdfs/buildradonout.pdf. Because installing such a system does not ensure radon levels under 4 pCi/L, the guidance further recommends that “[t]he home should be tested after occupancy and the passive system should be activated [fan powered] if post-occupancy testing reveals radon levels at or above 4pCi/L.” See Building Radon Out at 30.
EPA also recently developed voluntary guidance addressing radon and many other indoor air quality issues in new home construction. The guidance, known as Indoor airPLUS, calls on builders of new homes in Zone 1 areas to use radon control techniques and to provide home owners in Zones 1 and 2 with radon testing kits and instructions for their use. See http://www.epa.gov/indoorairplus/about.html.
Certain non-governmental organizations have developed consensus-based, technical standards for radon control techniques in new home construction. For example, the International Residential Code (IRC), a model building code developed by the International Code Council, contains a radon control standard that calls for a passive (no fan) sub-slab or sub-membrane depressurization system to be installed in homes located in Zone 1 areas. Because the IRC standard is included as an optional appendix (“Appendix F”) jurisdictions that adopt the IRC as part of their building code must explicitly include Appendix F in order to establish the IRC’s radon control standard.
Another third-party standard is ASTM International’s ASTM E-1465 (“Standard Practice for Radon Control Options for the Design and Construction of New Low-Rise Residential Buildings”). One of the main differences between this model standard and the IRC Appendix F standard is that the ASTM standard requires pre-occupancy radon testing; if the testing indicates unacceptable radon concentrations, a fan (active system) must be installed. (For a description of the differences between the two standards provided by the organization AARST, see http://www.aarst.org/images/Comparison_Appendix_F_and_1465_07_08.pdf).
State Policies
State and local governments can play an important role in reducing the risks from radon exposure. In addition to providing education and information to builders and consumers, they can enact policies to help ensure that homes are built with radon control techniques. These policies can reference an existing radon control standard, or they can modify and adapt existing standards and guidance.
There are a variety of opportunities for enacting state policies. States can include radon control requirements in state-wide building codes that are mandatory at the local level. States that have model state building codes can include radon control standards that localities must adopt if the local government chooses to establish a building code or radon standard. States can also establish radon control requirements for new, state-funded housing development projects. At the local level, many county and municipal governments have broad authority to adopt their own radon control requirements for new home construction.
The following states have incorporated minimum radon control requirements for new home construction into their residential building codes that apply throughout the state. Click on the links below for brief summaries of these policies.
There are many more states that have both state-wide residential building codes and a significant number of high and moderate radon potential areas, but do not address radon in their codes, These states include Indiana, Montana, Pennsylvania, Massachusetts, Utah, Connecticut, New Mexico, New York, Wisconsin, California, and Georgia. There are other states with high radon potential areas, such as Idaho and Nebraska, that have residential building codes that apply locally if the local jurisdiction elects to enact a building code. Watch for updates to this page as new policies are enacted.
Last Updated: Feb. 2010
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