Molds are organisms that grow indoors as well as outdoors. Outside, they’re an important part of the ecosystem. Indoors, they can be problematic.

You’re likely to find mold growing in the darkest, dampest spaces. More than a cosmetic problem, mold can damage your home and contribute to health issues.

Let’s examine the types of mold you’re most likely to find in your home, the potential impact on your health, and how to get rid of it.

Outside, molds help to break down plant and animal matter. As part of the fungi family, they release tiny spores that float through the air. These spores can enter your home via:

  • doors
  • windows
  • heating and air conditioning vents
  • clothing and shoes
  • pets

Inside, mold spores can’t grow unless conditions are right. The spores can latch on to a variety of materials, including fabrics, carpet, paper, and wood. Mold prefers spaces with lots of moisture and little light, such as:

  • in sinks, bathtubs, and showers
  • near leaky pipes
  • around windows
  • in basements, crawl spaces, and attics

Types of mold

Multiple types of mold can grow in the same area, and you can’t always differentiate the mold without testing. Fortunately, you don’t need to know the type to get rid of it. The most common indoor molds are:

  • Cladosporium. This mold is brown, green, or black. Cladosporium grows in both warm and cool locations. It’s most often found on wood, carpets, or fabrics, and in heating and cooling ducts.
  • Penicillium. This fuzzy mold is blue, green, or yellow. It’s often found under carpets, in basements, and in insulation, especially when there’s been water damage.
  • Aspergillus. Aspergillus is green, white, or gray with dark spots and a powdery look. This type of mold doesn’t need much ventilation. It thrives in fabrics, walls, attics, and basements, as well as on dry food items.

Although these molds aren’t found indoors as often as those listed above, you may still find them in your home:

  • Alternaria. This fuzzy mold is white with black spots. It tends to grow in fabrics and wallpaper, near windows and air conditioners, and in bathrooms and kitchens.
  • Aureobasidium. This mold is pink with black spots. It’s most commonly found on wood, walls, caulking, and grout.
  • Stachybotrys chartarum. Also called black mold, this greenish-black mold grows on things with a high cellulose content. It’s usually found on paper, fiberboard, and gypsum board.
  • Trichoderma. This mold is creamy-white, but turns green when it releases spores. It’s often found on wood, windows, and in bathrooms and kitchens.

Mold starts out as a little spot but expands quickly. You’ll usually notice it early on, unless it’s in an out-of-the-way location.

Mold can be black, white, spotted, or just about any color, and may appear powdery, cottony, or velvety.

If you notice a spot and aren’t sure if it’s just an old stain or a splotch of dirt, here’s how to tell if it could be a sign of mold:

  • It has a musty, earthy smell.
  • There’s a nearby source of moisture, but not much light.
  • You see warping, cracking, or peeling of whatever material it’s growing on.
  • A drop of bleach lightens its color in a minute or two.
  • Unchecked, mold will continue to grow. Dirt and old stains won’t.

Having mold in your home won’t necessarily make you sick. But it does have the potential to cause certain health issues.

Touching or inhaling mold spores can cause allergy-type symptoms such as:

  • runny nose and congestion
  • eye irritation
  • sneezing
  • coughing
  • sore throat
  • skin rash
  • headache
  • lung irritation
  • wheezing

You may be a higher risk for complications like infection if you have conditions such as:

In people with asthma, an allergic reaction to mold can trigger an attack. They may need inhalers to manage symptoms.

Exposure to a large amount of mold can cause a more serious reaction. This type of exposure is usually due to occupational or workplace hazards rather than from exposure to mold in your home.

Some types of over-the-counter (OTC) medicines may help relieve mild to moderate symptoms. These include:

If you have more severe symptoms, be sure to follow up with your doctor.

In many cases, you can get rid of household mold yourself. Mold can be removed with:

  • commercial products
  • soap and water
  • a bleach solution of 8 ounces of bleach per 1 gallon of water

Before you begin:

  • Open any windows.
  • Wear protective eyewear, nonporous gloves, and a face mask or N-95 respirator.
  • Never mix other cleaners or ammonia with bleach, as it can create toxic fumes.

Use a brush to scrub mold off surfaces, making sure you get it all. Porous materials, such as carpeting, furniture, and ceiling tiles, may have to be discarded. Don’t paint or caulk until you’re sure all the mold is gone.

Seek a professional contractor with experience in safe removal of mold if:

  • there’s a large amount of mold or it’s hard to reach
  • you’ve had severe water damage
  • you’re at high risk of symptoms from mold spores

Mold spores are everywhere and are part of the world we live in. It’s impossible to get rid of mold entirely, but there are ways to make your home inhospitable to mold. This includes taking the following steps:

  • Fix water leaks immediately. Clean up excess water and use fans to dry the area.
  • Repair or replace windows that leak or sweat, as moisture may collect on the frame and sill.
  • Maintain low humidity in your home with air conditioners and dehumidifiers. Change filters and service air conditioners and furnaces as recommended.
  • Don’t carpet rooms such as bathrooms, laundry rooms, or basements.
  • Keep your home well ventilated. When possible, exhaust fans should vent outside. Use exhaust fans or open windows when showering or bathing.
  • Use cleaning products that kill mold. Wipe down tiles and allow shower curtains to dry.
  • Don’t leave wet towels or clothes in a pile or sitting in a laundry hamper or washing machine.
  • Make sure water drains away from your house.

Mold in your home doesn’t always cause health problems, but it should always be removed. Mold can cause damage to your home and can lead to eye, nose, throat, and lung irritation.

If you have a mold allergy or chronic lung condition such as asthma, you’re at risk for more severe symptoms and complications.

A few home maintenance chores can make it harder for mold to grow indoors. If you happen to have spots of mold in your home, you can take steps to remove the mold yourself.

But if it’s a big job, or if you have respiratory problems, you’re better off with a professional contractor who can safely remove mold and make the necessary repairs.