Mold is a serious health hazard in the home environment, as it produces allergens, irritants, and in some cases, potentially toxic substances. Further, mold can trigger respiratory problems such as asthma in vulnerable and allergic populations. Therefore, preventing and eliminating mold problems is a crucial part of ensuing quality housing conditions.

Controlling mold problems in the home environment is largely dependent on controlling the level of moisture in the home, because mold cannot grow without moisture. Further, excessive moisture in the home is cause for concern as it can also cause or contribute to structural home damage and other housing hazards to human health such as cockroachesdust mites, and peeling lead paint.

Fortunately, there are ways to prevent and control excessive moisture, and therefore mold growth, in the home environment—both practical measures for residents as well as precautionary measures during construction or renovation. Please visit the “How to Control Moisture” section of this website for additional information such as practical tips, telltale signs, and likely sources of moisture both inside and outside the home.

In addition to preventative measures, visual inspections for mold should be performed periodically for the early detection of potential problems. Mold may be clearly visible or it may be hidden under furniture and carpets, in cabinets, and in crawlspaces or attics. When assessing mold problems in the home environment, it is important to know such potential hiding places and visually inspect all likely areas that are reasonably accessible. In some cases, mold will not be discovered even after searching typical hiding places, but a musty odor or related health problems will indicate a mold problem. In these instances, mold may be hidden on the backside of such materials as drywall, wallpaper, paneling, and carpet pads or inside wall cavities and ductwork. Investigation of such hidden mold problems is more complicated as actions such as peeling off wallpaper may disturb the mold and cause widespread dispersal of mold spores. Expert assistance may be required for such disruptive actions.

The most reliable way to identify a mold problem is through visual inspection. Because all molds should be treated similarly (safely removed, while addressing underlying moisture problems), there is no need to identify mold by type prior to remediation. However, bulk or surface sampling may be helpful in identifying specific mold contaminants in connection with a medical evaluation or in confirming the presence of mold if a visual inspection is unclear. Bulk sampling involves removing and collecting visible mold from surfaces, while surface sampling involves wiping a surface or stripping it with tape to collect specimens.

Airborne fungal testing is rarely appropriate but may be useful if, for example, building occupants are experiencing symptoms that seem to be mold-related, and a visual inspection and sampling have failed to locate mold. Airborne testing does not provide reliable data on the average mold content in a home—instead, it provides a “snapshot” of mold levels, which vary considerably over the course of hours, days, weeks, and months. Airborne fungal tests also are expensive and there currently are no standards for determining whether measured fungal concentrations are safe. Extensive airborne testing should be reserved for specialized cases, such as when health problems persist in a complex building environment with no discernable source of the problem. In such a setting, expert assistance should be engaged.

The New York City Department of Health & Mental Hygiene and the US EPA have developed separate but complementary guidelines for assessing and remediating mold in indoor environments. These guidelines contain detailed recommendations on the appropriate remediation activities for varying sizes and locations of mold contamination in various structures.

The NYC Guidelines contain five levels of mold remediation protocols. The most basic techniques apply to areas of 10 square feet or less, and include training workers on safe cleanup methods; protecting workers with disposable respirators, gloves, and goggles; vacating people from the work area; suppressing dust; removing and disposing of contaminated items that cannot be cleaned; and final cleaning of work areas and work area-egress locations. In addition to containing more protective measures such as containment for larger mold problems, the Guidelines also address remediation of HVAC systems.

EPA advises that if the moldy area is less than 10 square feet in total size, non-professionals can usually manage the cleanup by following some basic precautions and procedures. Larger jobs may require the services of a contractor who should have prior experience cleaning up mold.

When a manageable mold problem is identified in the home environment, the following are some basic steps that individuals, landlords, and homeowners can take to remove the mold:

  • Remediate the moisture source immediately. Mold cannot grow without water; therefore, controlling underlying moisture problems must be an integral part of removing mold.
  • Wear gloves, goggles, and appropriate respiratory protection during all mold remediation activities. Both EPA and New York City recommend the N-95 respirator available on the Internet and at most hardware stores for approximately $12-25.
  • Take photos of the moldy surfaces. These may be useful in the future should the need to document the problem arise.
  • Determine if it is possible to clean the moldy area or not. Non-porous and semi-porous materials (e.g. metals, glass, hard plastics, wood, and concrete) can generally be cleaned and reused. Porous materials (e.g. fabrics, ceiling tiles, insulation, wallboard) may be cleaned, but it is preferable that they be removed and thrown away, as it is extremely difficult to ensure complete removal of the mold.
  • Remove belongings from the clean-up area.
  • Clean the moldy area as soon as possible with either a detergent/soapy water solution or a baking soda and vinegar solution. Thoroughly dry the area and immediately dispose of all sponges or rags used in both the cleaning and drying process. Chemicals such as chlorine bleach are not recommended for routine mold cleanup.
  • When finished cleaning the visible mold area, clean all nearby surfaces and scrub or vacuum the floor.
  • Make sure the area is well ventilated until all surfaces are dry.
  • Regularly check the area for signs of recurring water damage and new mold growth. If the mold returns, it may indicate that the underlying water problem has not been appropriately addressed.

Sources and Additional Information:

Affordable Comfort –

A Brief Guide to Mold, Moisture, and Your Home –

Community Environmental Health Resource Center –