7 Signs You Have Mold in Your Home and What to Do

Closeup of black mold on a home surface

The Spruce / Sarah Lee

Project Overview
  • Working Time: 15 mins - 1 wk, 3 days
  • Total Time: 15 mins - 1 wk, 3 days
  • Skill Level: Intermediate
  • Estimated Cost: $10 to 5,000

Mold spores are everywhere: some are beneficial, some are destructive. Mold spores become a problem in your home when they find a warm, moist spot and begin to feed on organic matter and grow. Mold can be destructive and harmful to your health if it takes hold in your home.

Luckily, there are certain warning signs that mold is present to help protect your health and property before the situation becomes extreme. Learn these seven signs that you may have a mold problem.

How Often to Check For Mold and Remove It

After learning the warning signs, always do a thorough check of your home if you suspect mold growth. Cleaning mold infestation or removal of damaged surfaces should be done immediately. Mold won't easily go away when left on its own.

Before You Begin

The most common molds that most homeowners encounter can be classified into three categories: allergenic, pathogenic, and toxic.

  • Allergenic molds can require removal by a professional, but most allergenic molds can be removed with home disinfecting products.
  • Pathogenic molds can be controlled with disinfectants but large colonies require professional removal.
  • Toxic molds are the most harmful and require a professional to kill the mold and dispose of any affected materials.

The Centers for Disease Control and Prevention does not recommend testing for mold because each type affects individuals differently and there are no scientific standards for what is an acceptable level of every type of mold. They do recommend that all types of mold be removed safely.

What You'll Need

Equipment / Tools

  • 1 set protective mask, gloves, and eyewear
  • 1 spray bottle
  • 1 microfiber cloth
  • 1 soft-bristled brush
  • 1 set measuring cups or spoons
  • 1 plastic bucket or large bowl


  • 1 bottle chlorine bleach
  • 1 bottle all-purpose cleaner
  • water


Materials for getting rid of mold in the home

The Spruce / Sarah Lee

7 Signs You Have Mold in Your Home

  1. Visible Discoloration or Staining

    If you see grey, black, green, or bluish specks along grout lines, on walls, or other surfaces, it is most likely mold. Keep an eye out for pink, red, or brown streaks, as well. The texture of mold can be powdery, fuzzy, or slimy. Dark water stains on walls, floors, or ceilings usually indicate the presence of mold.

    Action to remove the mold should be taken immediately whether you can do it yourself or need a professional.

    Discoloration and mold on bathroom tile and grout

    The Spruce / Sarah Lee

  2. Musty Odor

    If your eyes are the first detector of mold, your nose runs a close second. Any whiff of a musty, earthy, or sour smell indicates that mold is present even if you don't see visible signs. When you detect an odor, become an investigator until you discover the source. If you don't see mold but still smell an odor, you may need a professional to investigate hidden colonies of mold in walls, crawl spaces, or along home foundations.

    Once the source of the mold is found, it should be cleaned up or damaged areas removed immediately.

    Damaged walls harboring mold colonies

    The Spruce / Sanja Kostic

  3. Damp Walls, Upholstery, Floor, or Cabinetry

    If surfaces feel damp—walls, floors, furniture, cabinetry—the level of humidity in the home is too high. High humidity levels will encourage mold growth in visible and non-visible spots like inside couch cushions, mattresses, or walls.

    To help reduce humidity, add a dehumidifier or run your HVAC system more frequently. Clean or remove any mold growth found.

    cleaning a cabinet with a cloth

    ​The Spruce / Ana Cadena

  4. Leaky Plumbing

    Even a small, slow leak can add enough moisture to encourage mold growth. Check all plumbing connections inside and outside the house regularly, repair leaks as quickly as possible, and take steps to remove the mold.

    Closeup of a leaky pipe

    The Spruce / Sarah Lee

  5. Moisture Condensation

    If you see droplets of water on walls, windows, windowsills, or around a refrigerator, freezer, or air conditioner coils, mold is sure to follow. Condensation occurs because the surfaces are typically colder than the air or other surfaces in the home.

    Take steps to insulate or repair leaky spots around these areas or empty drip pans to help prevent mold growth.

    Closeup showing mold on a windowsill

    The Spruce / Sarah Lee

  6. Taste

    If your cup of coffee tastes off, it could be there is mold in your coffee maker. Small appliances that use water and water dispensing systems in refrigerators are perfect breeding grounds for mold growth.

    Regular cleaning and proper maintenance will help keep mold at bay.

    Closeup of a coffee maker

    The Spruce / Sarah Lee

  7. Allergic Reactions

    If someone in your family begins to show signs of an allergic reaction - sneezing, coughing, rashes - that won't go away, it could be because of mold. Consult with your physician and if mold exposure is the cause, take action to remove the mold.

    Person itching skin due to a possible allergic reaction to mold

    The Spruce / Sarah Lee

Tips to Reduce Mold in Your Home

  • Check plumbing regularly for leaks and repair them quickly.
  • Reduce the humidity level in your home. Use circulating fans and vent fans in your kitchen and bathroom.
  • Wipe up spills and dry carpeting, upholstery, and laundry as quickly as possible.
  • Increase air circulation in your home.
  • Keep roofs repaired and gutters free of debris.
  • Clean and perform maintenance on appliances regularly.
Article Sources
The Spruce uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Mold and Health. U.S. Environmental Protection Agency

  2. Basic Facts About Mold and DampnessCenters for Disease Control and Prevention

  3. You Can Control Mold. Centers for Disease Control and Prevention

  4. Mold. Centers for Disease Control and Prevention