Radon Control in New Home Construction | Environmental Law Institute

ELI Policy Brief

Background

Radon is a radioactive gas found in soil and rock. Radon gas can move into buildings through cracks and other openings in the foundation, and indoor radon exposure is responsible for about 21,000 lung cancer deaths in the U.S. each year. This makes radon the second leading cause of lung cancer overall and the leading cause among non-smokers. U.S. EPA, Health Risk of Radon.

Elevated indoor radon levels have been found in every state and can be found in any area. The only way to know the radon level in a particular building is to test the building for radon.

EPA has established a radon “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. Because there is no known safe level of exposure to radon, EPA also recommends that people consider fixing their home where radon levels are between 2 and 4 pCi/L. U.S. EPA, A Citizen’s Guide to Radon (2016).

The concentration of radon in indoor air is affected by the way buildings are designed and constructed. When a new building is constructed, radon control techniques (also referred to as radon-resistant new construction) can be used to help keep radon from entering the home. EPA’s Radon-Resistant Construction Basics and Techniques describes the key elements of a radon control system and provides links to other technical resources. EPA recommends that all homes, even those built with radon-resistant features, be tested. U.S. EPA, Basic Radon Facts.

Non-governmental organizations have developed consensus-based technical standards for radon control in new home construction. For example, the International Residential Code (IRC), a model building code developed by the International Code Council, contains an optional radon control standard that calls for a passive sub-slab or sub-membrane depressurization system to be installed in homes located in areas of high average radon potential. The 2021 version of the IRC added to the radon standard a requirement for post-construction radon testing, and mitigation if the radon level is high. Because the radon standard is included as an optional appendix (“Appendix F”), jurisdictions adopting the IRC must explicitly include Appendix F in order to incorporate the radon control standard into their building code.

The Indoor Air Association (AARST) has developed several consensus-based, ANSI-approved radon standards, including radon mitigation standards for residential and non-residential buildings. See AARST Radon Standards.

In addition, EPA has developed voluntary guidance addressing radon and many other indoor air quality issues in new home construction. Indoor airPLUS requires new homes in areas of high average radon potential to include radon control techniques. The standard recommends that radon-resistant features be installed according to ANSI/AARST standards and that all homes with or without radon-resistant features be tested for radon prior to occupancy. EPA expects to update its Indoor airPLUS standard, including the radon requirements, in 2024. US EPA, Indoor airPLUS.

State Policies

State, tribal, and local governments can play an important role in reducing the serious risks from radon exposure. In addition to providing education and information to builders and consumers, they can enact policies to ensure that new buildings are constructed with radon control techniques. One key policy opportunity for protecting public health is to include radon control requirements in residential building codes. States and other jurisdictions that have adopted building codes for residential construction can revise those codes to reference and/or adapt an existing radon control standard.

The following states and the District of Columbia have incorporated mandatory radon control requirements for new home construction into their residential building codes. There are many more jurisdictions with residential building codes that can benefit from similar policies.

Some states, including Florida, Virginia, and Utah have established radon control standards that must be used by local jurisdictions if the locality chooses to adopt a radon control standard.

Last Updated: November 2019