Moisture Control: A Key Factor for a Healthy Indoor Environment

EPA’s mission is to protect public health and the environment. While a large part of this mission involves protecting the air and water outdoors, we also need to make sure that people have the tools and information they need to keep the air clean in the areas where they spend up to 90 percent of their time – indoors.  And the agency is doing that through voluntary actions and information sharing, not regulations.

Some of the biggest threats to indoor air quality stem from moisture issues. Leaking roofs, plumbing problems, condensation issues, poor indoor humidity control, and lack of drainage around the base of buildings are commonly reported causes of moisture problems in the United States. Not only does excess moisture damage the structural integrity of buildings, it can increase people’s exposure to mold and other biological contaminants. Such exposure is associated with increases in the occurrence and severity of allergies, asthma and other respiratory illnesses. And, climate change will only worsen these issues as we see an increase in the frequency and intensity of severe storms and flooding that damages homes and buildings.

The good news is moisture problems in buildings can be controlled with steps that can be taken to make buildings more moisture resilient. For example, design landscaping to slope away from building foundations. Doing simple steps like this can prevent economic losses on multiple fronts by avoiding building damage as well as negative health impacts as it makes our indoor spaces healthier and more comfortable.

That’s why EPA pulled together experts from across the country to develop new, practical, state-of-the-art guidance for controlling moisture in buildings.  EPA recently published the result of that work, entitled, “Moisture Control Guidance for Building Design, Construction and Maintenance.” Encouraging voluntary actions to control moisture and other indoor contaminants will be a critical part of our climate adaptation strategy for ensuring healthy buildings as we continue to address our changing climate.

The key to controlling mold and many other indoor contaminants is moisture control.  It’s a simple concept, but it takes attention to detail to get it right. That’s why this practical guidance will be helpful to people who design, build or keep buildings working. Building professionals who incorporate the principles provided in this guide can enhance the health and productivity of Americans and the sustainability and resiliency of our communities. While this guidance is primarily for building professionals, EPA also offers mold and moisture control guidance for homeowners and residents at

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