Mold is a type of fungi that is everywhere around us. However, mold can be a problem when it grows unchecked inside a home. If there is sufficient moisture, along with a food source such as wallpaper, drywall, wood, carpet, or any organic substance, mold may proliferate in your home. If you think you have a mold problem in your home, the following questions and answers may address many of your concerns:
How does mold get into my home?
Do I have mold in my home?
Is my mold the black "toxic mold" I've heard about?
How is the mold in my home bad for me?
Can you test my home for mold?
Where is the moisture source for my mold?
My landlord won't fix my moisture problem, what can I do?
What are my options to remove the mold?
How do I know the remediation or cleanup is finished?
Can I contact the Milwaukee Health Department to learn more about mold?
Where can I find additional information about mold?
Molds are everywhere and most grow naturally outdoors. Mold spores are present in all indoor environments and cannot be eliminated from them. Molds can be easily brought into buildings through open windows and doors, ventilation and air conditioning systems, as well as on pets, clothing, or shoes. Spores are not visible to the naked eye, and are easily carried through the air. When spores land in a moist environment with an adequate food source, mold begins to grow.
It is not practical to expect a building to be completely free of mold. More than 1,000 different types of mold have been found in U.S. homes. However, mold growth on indoor surfaces is a sign of an unmitigated moisture presence, the cause of which should be identified and corrected. Regardless of the type or quantity of mold, it should be removed.
Mold first appears as black, grey, green or other colored blotches or stains. It can grow on ceilings, floors, on or behind walls, in or under carpets, window sills and many other places. Mold grows most easily in places where moisture is a problem due to leaks, condensation, and/or a lack of ventilation or insulation. It commonly gives off a musty, stale odor that may signal to you that you have a mold problem. If you are a tenant, notify your landlord immediately if you suspect mold in your home. If there is no visible mold, but you still suspect you may have a mold problem, consider consulting a qualified indoor air quality specialist. However, keep in mind testing is only advised in rare instances.
The term "toxic mold" is misleading, black or otherwise. To date, no scientific evidence exists to positively link residential exposure to mold with specific toxic effects. The majority of human exposures to mold toxins have occurred from ingesting moldy food. Current guidance of federal and professional organizations is that mold growth should be controlled in an appropriate manner, regardless of the type of mold.
Some people are sensitive to molds, about 10% of the population is allergic to one or more types of mold. Exposure to molds can cause symptoms such as nasal stuffiness, eye irritation, wheezing, or skin irritation. Even greater concern exists for persons with severe mold allergies, asthma, or immune-compromised systems (transplants, chemotherapy, AIDS, newborns, etc.). If you have any concerns about your health, please consult your physician. For more information about the science on mold and human health click on the links below:
The City of Milwaukee Health Department does not recommend routine sampling for molds or provide mold testing services. If you can see or smell mold, then you have a mold problem and testing or sampling is typically not necessary.
Testing for mold can be timely and expensive. Identifying the moisture source and developing a plan to remove the mold is recommended as a better use of your time and money. In addition, there are no agreed upon health-based standards for human exposure to mold or mold spores and no specific number that defines either safe or unsafe mold exposure. Some experts have proposed airborne mold guidelines; however none of these have been adopted by regulatory agencies. Testing is only advised in rare instances and should be discussed with an indoor air quality specialist. If you have discovered mold, your next move should be to investigate the source of the moisture which invited the mold into your home.
Moisture control is the key to mold control. If you are a tenant, work with your owner, landlord or property manager to identify any maintenance issues which may be the source of the moisture intrusion. Some common places moisture can invade your home are roof leaks, plumbing leaks, drainage problems, damp basements and crawl spaces, steam from the bathroom or kitchen without proper ventilation, condensation resulting from poor insulation or ventilation, humidifiers, wet clothes drying inside the home or a clothes dryer venting indoors, or poor ventilation of combustion appliances. Please note from these examples that not all moisture problems are necessarily the result of a maintenance issue and it is important you work with your owner, landlord or property manager to resolve the issue.
Flooding can also provide ideal conditions for the growth and proliferation of mold. For advice on how to clean up after your home has been flooded, click here.
If you have discovered your home's moisture intrusion is the result of a maintenance issue, report it to your owner, landlord or property manager. If they are unresponsive, you can contact the Department of Neighborhood Services (DNS) at (414) 286-2268 to issue a complaint. Please keep in mind, DNS should be your second call, not your first.
In addition, evacuation in response to mold should be rare. There is no established level of airborne mold that is accepted as unsafe for the general population. We are exposed to many of the same mold species indoors as well as outdoors. Ultimately the decision to vacate a space should rest with the individual occupant, parent or guardian and be based on the amount of exposure, individual sensitivity, and the advice of a medical doctor.
Preventing mold growth requires controlling the moisture source. This may be as simple as using a dehumidifier or fixing a simple leak. The affected area(s) should be allowed to dry thoroughly.
Small areas of mold growth on non-porous surfaces, what you may typically find in your bathroom, on a wall, or a window sill, can usually be cleaned with a damp cloth and cleaning agent (e.g. window or bathroom cleaner). If sewage release occurred, a bleach (between 1% and 5% chlorine) solution may be necessary to disinfect*.
For clean up instruction on larger mold problems (approximately 10 square feet), click here. If cleanup of the mold infected areas is too overwhelming for you or requires the removal of mold contaminated surfaces (including drywall, carpeting, or wood flooring), consider the use of a mold/water cleanup service or mold remediation contractor. Please note that there are no state or local recognized mold certifications. It is recommended you follow the Tips for Hiring a Mold Remediation Contractor/Consultant from the Wisconsin Department of Health Services when choosing remediation assistance.
*WARNING: Do not mix bleach with other household cleaners. Some household cleaners contain ammonia. If ammonia is mixed with chlorine bleach, a toxic gas can form, causing serious injury or death.
*CAUTION: The bleach solution is irritating and harmful to the skin, eyes, and clothing. Avoid direct contact with the bleach by wearing rubber gloves, respirator and goggles during the entire mixing and cleaning process.
You must have completely fixed the water or moisture problem before the cleanup or remediation can be considered finished. Just cleaning the mold does not stop mold growth, you must fix the water problem or the mold can return. A home will continue to have low levels of mold even after mold removal and mold remediation is finished. Leaving a few mold spores behind is not a problem if the underlying moisture problem has been corrected.
Once you have completed mold removal, visible mold and moldy odors should not be present. Revisit your site shortly after cleanup and it should show no signs of water damage or mold growth. Please note that mold may cause staining and cosmetic damage. Consider using dehumidifiers and fans to dry the now-cleaned areas for a few days, then check them (by sight and smell) for mold. If you discover more mold, clean again.
If you believe you still have a moisture issue, work with your owner, landlord or property manager to repair it immediately. If you think you may still have a mold issue and you are unable to remedy it, consider consulting a mold remediation contractor.
The City of Milwaukee Health Department's Disease Control and Environmental Health Division is available as a resource to answer any questions you may have about mold, including the health effects associated with mold exposure and how to remediate it from your home. If you are a City of Milwaukee resident, feel free to call (414) 286-3521 with your questions.