Mold Frequently Asked Questions (FAQs)

The Minnesota Department of Health (MDH) receives many inquiries each day concerning mold. The following is a list of the most frequently asked questions.

Does MDH test homes for mold?

No - MDH does not conduct any testing for mold and in most cases does not recommend testing. For more information go to Testing for Mold. If you decide you want to continue with testing, here are some guidelines for selecting a IAQ consultant:

What is MDH doing about mold?

The Minnesota Department of Health Indoor Air Unit assists with mold issues through the following activities:

  • Provide limited technical assistance to local public health, schools or the public when requested.
  • Develop and distribute fact sheets and resources on mold and moisture control.
  • Provide “Best Practices” guidelines for schools regarding investigation and remediation of mold problems.

I had a consultant test my home for mold, what do the results mean?

Testing for mold can be done through a variety of techniques such as air, surface, bulk or swab sampling to identify the presence of mold. At present there are no state or federal standards established for unsafe levels or types of mold.

There are over 1000 different molds that have been identified indoors and the health effects of mold growth in homes are not well understood.

If testing for mold is done, it is critical to establish a sampling methodology to appropriately address the investigator’s hypothesis. This usually involves collecting control samples (such as outdoors) to compare to samples from the suspect area. For example, if the molds found indoors are different from molds outdoors, or if the levels of molds are significantly higher indoors from outdoors, this may suggest a potential indoor mold problem. 

How much mold is too much?

Any mold growth in a building should be considered a problem because it is damaging to building materials.  In addition, it is safest to treat any indoor mold growth as a "potential health hazard" which needs to be corrected because there are no health standards for mold and the health effects of mold are not well understood.  Any amount or type of mold should be removed and the moisture problem that allowed its’ growth should be fixed.

Is it important to know what type of mold is present?

It is usually unnecessary to know what type of mold is present.  If someone is recommending mold testing to you, be sure to ask how identifying the type of mold will be used in a practical manner to answer health questions or to fix the problem. Because of the limited research on molds and its potential health effects, MDH has taken a precautionary position that no type of mold growth should be tolerated in an indoor environment. More information can be found on the Testing for Mold Web page.

Is there a “killer mold”?

Indoor molds are unlikely to be life threatening. Livestock have died from eating moldy feed and fungal infections can be fatal to humans, although this is rare. There is no specific mold that creates a life threatening situation by its mere presence.

Much concern was raised about the mold species Stachybotrys chartarum because it was found in homes of infants with an unusual “bleeding lung disease” in the Cleveland, Ohio area. Stachybotrys was labeled by the media as a “killer” mold because some of these infants died. Recently, however, the Centers for Disease Control (CDC) and other experts reviewed the investigations of the Cleveland case and concluded that an association between the exposures to mold and the illnesses was not proven.

Despite the recent focus on Stachybotrys, many kinds of mold may affect an individual’s health. Although healthy individuals are not likely to experience severe effects from small amounts of mold growing indoors, some people are more susceptible and hence, at greater risk than most of the population. It is generally prudent to assume that some people might experience problems when mold is allowed to grow unchecked indoors and the likelihood of health effects increases as the amount of mold or the duration of exposure increases.

I’ve been feeling sick lately. Is it from mold?

Some people are allergic to mold and some experience asthma symptoms in the presence of mold. Certain types of infections are caused by mold such as athlete’s foot. A few molds can cause infections (such as aspergillosis) in individuals with severely weakened immune systems, for example persons with to advanced HIV or cancer patients undergoing chemotherapy. Mold has been alleged to cause other health effects in some cases but these are not well understood.

If there is visible mold growth in your home it should be removed whether or not you are having health problems. It is important to keep an open mind and consider other possible causes of illness. As with any illness, you should see a physician to try and determine the cause of the symptoms.

What is causing the mold growth in my home?

Mold must have a source of moisture in order to grow. Some common moisture sources are:


  • Humidifiers
  • Cooking and dishwashing
  • Bathing / Showering
  • Plumbing / Roof leaks
  • House plants
  • Firewood stored inside
  • Unvented clothes dryer/indoor clothes line
  • Improper venting of combustion appliances
  • Occupancy load


  • Flooding
  • Rain or snowmelt
  • Seasonal high humidity
  • Ground moisture
  • Wet building materials

The best way to identify a mold problem is to conduct a visual inspection and moisture investigation to identify the moisture sources.

Will painting over mold solve the problem?

NO - The mold needs to be removed from the materials it is growing on with soap and water then dried thoroughly. If it is a porous material that cannot be cleaned, such as drywall or particle board, it needs to be removed and replaced. The moisture problem needs to be corrected.  If you simply paint over the problem the paint may not adhere and the mold problem may redevelop on the painted surface.

Where can I find a “licensed” mold investigator?

Neither the state of Minnesota nor any federal agencies "license" mold investigators. Some professional organizations or universities may offer courses in mold investigation and provide attendees with certificates, but these are not licenses issued by a governmental agency.

What are mycotoxins?

Many species of mold have the capability to produce metabolites as part of their growth process that are referred to as mycotoxins. The molds that are capable of producing these toxins do not do so in all situations. Therefore, just because a mold has the capability to produce a mycotoxin, does not mean that a toxin will be produced if a particular mold with the capability is present. Specific conditions, which vary among different types of mold, are required for mycotoxin production. The presence of mycotoxins does not necessarily correlate with individual exposures or health effects. As previously stated, any indoor mold growth should be cleaned up and the moisture problem resolved regardless of the presence of mycotoxins.

What can I do about mold in my apartment/rental unit?

If you see or smell mold in your apartment it should be cleaned up and the moisture source that caused it should be repaired. Inform your landlord in writing of the problem as soon as you are aware of it. There are no state or federal laws dealing specifically with mold in rental units. If adopted where you live, local property maintenance codes require rental units be maintained by the landlord to be habitable and in good repair. Contact your city or county housing or health inspector. More information can be found on the Mold in Rental Housing Web page.

Is any money available to help fix the mold problem in my home?

The Minnesota Department of Health does NOT have any funding available to assist in clean up of mold in homes.

The Minnesota Housing and Finance Agency does have LOANS available through its Fix Up Fund program to improve the livability of your home. For more details on this program call their office at 1-800-710-8871.

You can also apply for valuation reduction of your homestead property, if the mold damage exceeds $20,000. Contact your local property tax assessor. The statutory citation is MN statutes 2004, section 273.11, subd.21.

Will my homeowner’s insurance pay for mold damage?

The Minnesota Department of Health does not have information regarding homeowner’s insurance. It is prudent to review your policy to determine what is covered and how it must be reported.

I think the mold in my home was caused through faulty building practices, what do I do?

The Minnesota Department of Health cannot provide you with that information. Homeowner’s should review any warranty provided by the builder. Minnesota State Statute Chapter 327A, requires a warranty on new homes. A copy of the statute can be found on the State Revisor’s website.

This new home warranty is not something that is enforced by the state or city, but is a contract between the builder and the homeowner. The levels of work covered are time sensitive. Certain items are only covered for a year from the time the home is built, others for a longer period of time The homeowner should contact the builder to report problems as soon as they become aware of the problem. If the problem cannot be resolved between the two parties, then mediation services can be contacted. This is usually the best way to settle the dispute. If mediation services are not able to resolve the dispute legal action is an option, such as filing a civil suit in small claims court.

The Minnesota Department of Commerce may be able to assist homeowners. They can be contacted via email or telephone call. You need to state which type of licensed service (in this case a builder) you wish to file a complaint about, and your inquiry will be directed to an investigator who handles the cases in that industry. The investigator will usually be able to tell you if your complaint is something they are able to investigate. The investigators cannot provide legal advice. Complaints must be submitted in writing before an investigation can begin. Complaints can be filed by contacting the Market Assurance Division of the Department of Commerce:

What does mold look like?

The following are some pictures (from U.S. EPA) of mold growing on various materials. These are only examples of some types of mold.

photo of mold on a ceiling Mold growing on ceiling and walls

photo of mold growing on the back side of wallpaper

photo of water stain on a basement wall

photo of mold on firewood Mold growing on firewood.

Updated Tuesday, June 23, 2015 at 01:08PM