How to Get Rid of Mold in Your Home

Mold is an inescapable part of nature, thriving in garden soil, on concrete walls, and in indoor spots like sink drains. While a small amount of grout mold isn't a cause for panic, understanding how to manage and remove it is important for your home’s health — and yours too. 

Types of mold

While some molds can make you sick (more on that later), others aren’t usually more than a nuisance. Here are the types of mold you might run into:

• Cladosporium: This is a very common mold that can range in color from blackish-brown to grayish-green. Cladosporium can grow inside and outside the home. Cladosporium likes things like dead plants, tree trunks, carpets, and upholstery.
• Aspergillus: This is a common mold both inside and outside the home. In fact, Aspergillus is so common, you’ve inhaled some before. 
• Penicillium: Another common mold, Penicillium prefers some human food like fruits, vegetables, and bread.
• Stachybotrys: Also known as black mold, Stachybotrys can grow on things like fiberboard and paper. If you’ve ever seen greenish-black spots of mold in your shower or other moist areas, it’s probably black mold. This isn’t nearly as common as other mold types.

How to inspect your home for mold

Mold only needs three things to thrive: moisture, a food source like drywall or dust, and 48 continuous hours to form. Jim Tomlinson, owner of Colorado-based company Mold Services, said if your home's humidity stays above 50% for two days or longer, it’s probably at high risk for mold growth.

Since mold thrives in dark, damp, and unventilated spaces, finding it requires a mix of visual inspection and using your other senses. Tomlinson emphasizes that by the time you see black spots, it's possible the mold has been developing for a while.

Use your senses

First, do a walk-through of your home.

The nose test: "We use our noses," Tomlinson says. "If we smell something that smells musty, then that’s indicative."

The humidity check: If a room feels "heavy" or damp, check the relative humidity. If it’s consistently above 50%, mold is likely growing somewhere out of sight.

Inspect the high-risk zones

Focus your search on areas where water enters or leaves the home.

Under sinks: Check the P-trap (the U-shaped pipe) for slow drips and look for warped cabinetry or bubbling floorboards.

The HVAC closet: Inspect the area around your furnace and water heater. Condensation from these units can soak into the surrounding drywall.

Basements and window wells: Look for efflorescence — a white, powdery mineral buildup on concrete — which indicates that moisture is pushing through the walls from the outside.

Attics and crawl spaces: Check for roof leaks or damp soil in crawl spaces. Tomlinson warns that even a slight haze on lumber can be a massive colony of Aspergillus.

Look for the hidden signs

Mold doesn't always look like fuzzy growth; sometimes your home will give you subtle clues.

Discolored grout: Pink, orange, or black stains in shower grout are early signs of a mold colony.

Peeling wallpaper or paint: If paint is bubbling or wallpaper is peeling away, moisture is likely trapped behind the surface.

Rusting nails: In basements or crawl spaces, look at the heads of nails in the floor joists. "That rust is indicative that it has been wet for more than 48 hours," Tomlinson said.

Miscellaneous things to inspect

The lumber check: Tomlinson said you shouldn’t assume a newly built home is mold-free. If you’re in a new build, look at the unfinished wood in the basement or attic. Mold can hitch a ride on lumber from the yard before the house is even finished.

Dust accumulation: Because mold toxins like to attach themselves to dust particles, heavy dust buildup in vents can be a reservoir for spores.

How to get rid of mold in your house

If your home has a mold problem, you have two goals: 1) remove the growth and 2) eliminate the moisture source. But that could be tough to do depending on how long the mold has been around, and where it is.

Pro tip: If you’re renting and you find mold in the home, your landlord may be responsible for cleaning it up.

Before you tackle any mold cleanup, the Environmental Protection Agency recommends wearing an N-95 respirator mask and gloves that are long enough to cover the middle of your forearm.

Once you’ve got your gear on, you can follow these expert-backed steps to clean your home safely:

1. Reduce the moisture

The easiest way to prevent mold is to keep things dry.

“Mold is everywhere. You can't really stop the spores; what you can control is the moisture or the relative humidity,” Tomlinson said.

Keep your house clean, dry, and well-ventilated — especially in the bathroom where water collects on tile grout or shower curtains. If your bathroom has a damp smell, investigate your drains. 

Check for mold in hidden spots:

• Under sinks
• Water heater closets
• Basement window wells

If you want to take more preventative measures, dehumidifiers are available for as little as $20.

Pro tip: The Environmental Protection Agency says if a moldy area in your home is less than 10 square feet, you may be able to clean it up yourself.

2. Scrub and spray hard surfaces

For small areas on non-porous surfaces like tile, the CDC recommends using a solution of no more than one cup of bleach to one gallon of water. Always wear an N95 mask and rubber gloves to avoid inhaling spores during the process.

To remove mold on exterior surfaces, use a pressure washer and make sure that everything is properly sealed (i.e. no holes in your siding or brickwork where mold can move in).

3. Professional remediation

To ensure your home is completely mold-free, remediation is your best step. This is the process where professionals find and remove the mold in your home. This often involves using negative air pressure to ensure spores don't spread to other rooms as well as removing microscopic contaminants in case any toxins hitch a ride on individual bits of dust.

Pro tip: If you’re suspicious of mold in your home, but don’t want to pay for a full inspection, you could have a professional test some smaller, problematic areas.

4. Dispose of porous materials

Tomlinson said visible mold is often just the tip of the iceberg. If you’ve found mold in your home’s drywall, carpeting, or insulation, it may be tough to completely remove it. The mold's "root" system can grow deep into these materials, possibly making surface-level treatments temporary or completely ineffective.

"If you just remediate and you don’t really clean the environment, that’s not being thorough,” he said.

Consulting a mold expert to check out the extent of the spread and guide you on next steps could save you repeated cleaning and long-term mold issues.

Mold risks if your home floods

Flood-damaged homes with heavy mold infestations should be handled by professionals.

Plus, flood-damaged houses are often contaminated with chemicals and human waste carried in by the floodwaters, which are more dangerous than the mold itself.

How dangerous is mold to your health?

Research published by the National Institutes of Health states the vast majority of mold spores “live in harmony with humans, rarely causing disease.”

Few mold species are toxigenic, meaning they produce poisons called mycotoxins. Stachybotrys chartarum — also known as black mold — is one of the most well-known. And while certain people are more at risk than others, mold could eventually cause health issues for anybody if it lingers long enough.

The Federal Emergency Management Agency warns that “infants, children, immune-compromised patients, pregnant women, individuals with existing respiratory conditions (allergies, multiple chemical sensitivity and asthma) and the elderly appear to be at higher risks for adverse health effects from mold.”

Mold toxicity vs. mold allergies

While most molds are not toxigenic, some can cause allergic reactions. The Cleveland Clinic estimates that about 3% to 10% of the general population has a mold allergy, which is different from toxicity.

Common types of molds that cause allergies:

• Alternaria
• Aspergillus
• Cladosporium
• Penicillium

Mold-related symptoms to watch out for

Tomlinson works with clients not only to detect and eliminate mold, but to educate them on the health risks involved; he said unfamiliarity with the symptoms can delay care.

"It makes for a really bad day for that one sick family member — when their family thinks they're crazy — and they take them to a doctor who isn't mold-savvy who tells them, 'It’s all in your head,’” he said.

Common symptoms of mold exposure include:

• Chronic headaches
• Brain fog
• Respiratory distress
• Persistent fatigue
• Coughing
• Itchy eyes
• Runny nose
• Wheezing
• Sneezing

If someone in your home has any of these symptoms, it may be wise to get your home inspected for mold. 

How to keep your home mold-free

Tomlinson said preventing mold is less expensive than professional remediation. These maintenance tips can save you thousands in future repairs:

• Clean HVAC ducts: Have your ductwork cleaned every two years to remove the dust that mold feeds on to thrive.
• Manage shower steam: Keep bathroom cabinets closed while showering to prevent moisture from being trapped in dark, cool cavities.
• Ventilation is key: If you don't have an exhaust fan, run a dehumidifier to bring humidity back below 50% within a few hours of bathing or cooking.

Standard home inspections often skip mold sampling. Tomlinson, a former real estate broker, recommends specialized testing during your "due diligence" period to ensure your biggest investment is truly safe.