The level of moisture in the home is crucial to achieving a healthy home environment. Too little moisture in the home can cause dryness of the nose and respiratory systems, while too much moisture in the home contributes to numerous health impacts, health hazards, and structural home damage. Asthma, allergies, and other respiratory illnesses are the main health impacts to children and other residents of homes with excessive moisture. Excessive moisture also causes or contributes to other hazards to human health such as mold, cockroaches, dust mites, and peeling lead paint.
Common Signs and Locations
Several common signs that conditions of excessive moisture exist in the home environment include the following:
- Rusting metal
- Condensation on piping and/or windows
- Rotting wood
- Deterioration of other structural items
- Visible water leaks and/or stains
- Discoloration of various surfaces
- Musty odors
- Standing water
These signs may be clearly visible or they may be hidden in places such as behind walls, under furniture and carpets, and in crawl spaces or attics. In assessing moisture problems in the home environment, it is important to know such potential hiding places and visually inspect all areas that are reasonably accessible. A low-cost moisture meter can also be used to test for moisture in inaccessible places.
Moisture problems inside the home can originate from problems both indoors and out. In general, preventing and eliminating moisture control problems involves removing, diverting, blocking, or otherwise controlling the source of moisture while also providing adequate ventilation. Some specific tips to prevent and eliminate excessive moisture in the home include:
- Regularly clean and maintain gutters, and ensure that they drain away from the foundation of the building structure.
- Install and run exhaust fans in the bathroom and kitchen or open windows for adequate ventilation.
- Vent all fans and appliances outside the home.
- Do not arrange or store items (furniture, storage boxes, etc.) so that they touch the interior side of exterior walls.
- Dry all clothes in a dryer that vents outside or use a clothesline outdoors.
- Cover dirt floors in basements and/or crawl spaces with plastic or other type of vapor barrier.
- Repair all plumbing leaks, roof leaks or problems, and cracks in foundation walls as soon as possible.
- Ensure that soil and landscaping near the structure’s foundation are graded away from the structure.
- Install floor drains or sump pumps in basements as necessary.
- Keep the temperature inside the home comfortable—neither excessively hot in the winter nor cool in the summer. Drastic changes between indoor and outdoor temperatures can contribute greatly to moisture problems.
Further precautionary steps can be taken to control moisture in the home environment during initial construction or any subsequent renovations.
National Academy of Sciences: Fact Sheet on Damp Indoor Spaces and Health
T. Platts-Mills, J. Vaughan, M. Carter, and J. Woodfolk, Journal of Allergy and Clinical Immunology, “The Role of Intervention in Established Allergy: Avoidance of Indoor Allergens in the Treatment of Chronic Allergic Diseases,” pp. 787-804 (November 2000).
U.S. Department of Energy: Guides and Case Studies for All Climates
U.S. Environmental Protection Agency:
- A Brief Guide to Mold, Moisture, and Your Home  [url] [pdf]
- [Español] Una breva guía para el moho, la humedad y su hogar  [pdf]
- Mold Remediation in Schools and Commercial Buildings
U.S. Department of Housing and Urban Development: About Mold and Moisture
Asthma No Attacks Hotline: 1.866.NO ATTACKS (1.866.662.8822)
General IAQ Hotline (IAQINFO): 1.800.438.4318
Sponsored by EPA, this hotline provides general information on indoor air quality and related pollutants.
Su Familia (Your Family) Helpline
The National Alliance for Hispanic Health sponsors this toll-free helpline (1.866.SU FAMILIA or 1.866.783.2645) to offer Hispanic consumers free, reliable, and confidential health information in Spanish and English and help navigate callers through the healthcare system. | En español: La National Alliance for Hispanic Health (Alianza Nacional para la Salud de los Hispanos) patrocina esta línea de ayuda gratuita (1-866-SU FAMILIA o 1-866-783-2645) para ofrecer a los consumidores hispanos información de salud gratuita, confiable y confidencial en español e inglés y ayudar a las personas que llaman sistema de cuidado de la salud.
Latest page update: November 29, 2023.