Mold FAQs

Two ingredients are needed for mold or mildew to grow. These include oxygen and moisture. With these two prevalent ingredients being available nearly everywhere, it should be no surprise that mold grows abundantly in many places. Mold spores are in the air and attach to moisture. Then if conditions are right, and high levels of moisture remain, the mold will grow.

In homes and offices, common places for mold to grow are kitchens and bathrooms where even a small drip can create an environment for mold to thrive. Leaks or condensation in HVAC systems or on ductwork can create mold problems along with any moisture that gets in the walls, ceilings or under floors.

Since we are exposed to mold and mildew nearly every day, small doses do not generally pose a problem. However, mold impacts people differently. Children, the elderly, asthma sufferers, and those with allergies are more susceptible to having reactions to the presence of mold. This can show itself in the form of respiratory issues that often resemble flu-like symptoms.

Some people are sensitive to mold or mildew. For these people, exposure to mold or mildew can cause symptoms such as nasal stuffiness, eye irritation, wheezing, or skin irritation. Some people, such as those with serious allergies to molds, may have more severe reactions like fever and shortness of breath.

Mold Allergy symptoms are very similar to the symptoms of other allergies such as dry skin, congestion, runny nose, sneezing, and itching. Outdoor mold can cause allergy symptoms in summer and fall (in some climates, the symptoms may be year-round). Indoor mold can cause allergy symptoms year-round.

Sensitive individuals should avoid areas that are likely to have mold, such as compost piles, cut grass, and wooded areas. Inside homes, mold growth can be slowed by controlling humidity levels and ventilating showers and cooking areas.

Specific Recommendations:

• Keep humidity levels as low as you can—no higher than 50% — all day long. Using an air conditioner or dehumidifier will help you keep the levels low, however, bear in mind that humidity levels change over the course of a day with changes in moisture levels and air temperature.
• Run a dehumidifier in enclosed spaces such as basements.
• Be sure the home has adequate ventilation, including exhaust fans.
• Add mold inhibitors to paints before application.
• Clean bathrooms with mold or mildew killing products.
• Do not carpet bathrooms and basements.
• Remove or replace previously soaked carpets and upholstery.

Generally, it is not necessary to identify the species of mold or mildew growing in a residence, and CDC does not recommend routine sampling for mold or mildew. Current evidence indicates that allergies are the type of diseases most often associated with mold or mildew. Since the susceptibility of individuals can vary greatly either because of the amount or type of mold or mildew, sampling and culturing are not reliable in determining your health risk. If you are susceptible to mold or mildew and mold or mildew is seen or smelled, there is a potential health risk; therefore, no matter what type of mold or mildew is present, you should arrange for its removal. Furthermore, reliable sampling for mold or mildew can be expensive, and standards for judging what is and what is not an acceptable or tolerable quantity of mold or mildew have not been established.

Standards for judging what is an acceptable, tolerable or normal quantity of mold have not been established. If you do decide to pay for environmental sampling for mold, before the work starts, you should ask the consultants who will do the work about criteria for interpreting the test results. They should tell you in advance what they will do, or what recommendations they will make, based on the sampling results. The results of samples taken in your unique situation cannot be interpreted without a physical inspection of the contaminated area or without considering the factors that led to the mold growth.

If you feel your property owner, landlord, or builder has not been responsive to concerns you’ve expressed regarding mold or mildew exposure, you can contact your local board of health or housing authority. Applicable codes, insurance, inspection, legal, and similar issues about mold generally fall under state and local (not federal) jurisdiction. You can also contact your county or state health department about mold issues in your area to learn about what mold assessment and remediation services they may offer. You can find information on your state’s Indoor Air Quality program at the Center for Disease Control (CDC) website. See CDC for an official list of the State Environmental Health Agencies.

If you believe you are ill because of exposure to mold in the building where you work, you should first consult your health care provider to determine the appropriate action to take to protect your health. Notify your employer and, if applicable, your union representative about your concern so that your employer can take action to clean up and prevent mold growth. To find out more about mold, remediation of mold or mildew, or workplace safety and health guidelines and regulations, you may also want to contact your local city, county, or state health department.

You should also read the U.S. Environmental Protection Agency (EPA) Guidelines, Mold Remediation in Schools and Commercial Buildings.

If you believe your children are ill because of exposure to mold or mildew in their school, first consult their health care provider to determine the appropriate medical action to take. Contact the school’s administration to express your concern and to ask that they remove the mold or mildew and prevent future mold or mildew growth. If needed, you could also contact the local school board.

Your local health department may also have information on mold, and you may want to get in touch with your state Indoor Air Quality office. Visit the Center for Disease Control (CDC) website for an official list of the State Environmental Health Agencies. CDC is not a regulatory agency and does not have enforcement authority in local matters. 

Also, the U.S. Environmental Protection Agency (EPA) publishes for guidelines, Mold Remediation in Schools, and Commercial Buildings.