How to detect where mold smell is coming from?

Author: Brooklyn Koepp  |  Last update: Monday, November 24, 2025

Leaks are common in doorways and windows that open to the outdoors, which can lead to dampness and in turn lead to mould. Entrances to the home are therefore a likely to be a source of damp smells, so try to check around the doorway for signs of mould.

What to do if you smell mold but can't find it?

Clean surfaces with a mixture of water and white vinegar or baking soda to neutralize odors. Inspect hidden areas like under carpets, behind walls, and inside ducts for any concealed mold. If the smell persists, consider professional mold inspection to identify and address any hidden mold sources.

How do I find the source of mould smell?

Check the usual culprits:

Cupboards and wardrobes, especially if they're not used much. Laundries, bathrooms, and other areas that routinely experience high humidity or dampness – bathroom ceilings are most common with mould forming close to external walls and windows.

Where is the moldy smell coming from?

That musty smell usually comes from basements, attics, crawlspaces, or other areas that lack proper ventilation and humidity control. Homeowners often find mold growing on paper products, books, cardboard boxes, and ceiling tiles. Mold will also thrive on wood, drywall, carpet, fabric, upholstery, and even dust.

How do you detect mold smell?

Persistent Smell Points to Mold

A persistently musty smell can be an indication of mildew in your home. Mildew is an early stage of mold that can grow on surfaces in your home, and can sometimes be mistaken for a surface just looking dirty.

How to search for hidden mold in your home

How to identify where a smell is coming from?

Places to Check for Bad Odors in Your Home
  1. Plumbing. A sewage smell in a house that comes and goes or is persistent could be caused by blockages in your plumbing. ...
  2. Soft Materials. Carpets, curtains and upholstery can absorb odor-causing compounds from cooking foods, mold and bacteria from humans and pets. ...
  3. Vents. ...
  4. Trash.

How to test for mold in the air?

How To Conduct Your Indoor Air Quality Test
  1. Step 1: Prepare the Test Area. When testing a room for mold air, close any doors, windows, or vents for at least 24 hours before sampling the air.
  2. Step 2: Follow the Mold Test Kit Instructions. ...
  3. Step 3: Label and Document. ...
  4. Step 4: Wait for the Results. ...
  5. Step 5: Interpret Results.

Why do I keep randomly smelling mold?

An olfactory hallucination, known as phantosmia, makes you detect smells that aren't in your environment. The odors you notice in phantosmia are different from person to person and may be foul or pleasant. You may notice the smells in one or both nostrils.

Can you smell mold behind walls?

If you don't see signs of mold, but you can smell it, it may be hidden in your walls. A musty smell indicates that mold is growing in your home. The smell of mold feels earthy, like rotting leaves or decaying wood in a dense, damp forest.

How to identify the source of mold?

Mold can grow anywhere there is adequate moisture or a water problem. The best way to find mold is to look for signs of mold growth, water staining, warping, or to follow your nose to the source of the odor. It may be necessary to look behind and underneath surfaces, such as carpets, wallpaper, cabinets, and walls.

What can smell like mold but not be mold?

Check humidity: Musty odors can often be due to excess moisture. Use dehumidifiers to reduce humidity, especially in rooms such as the bathroom, basement or other damp areas. Cleaning: Thorough cleaning is crucial. Clean carpets, curtains, furniture and other surfaces that absorb moisture regularly.

Are there mold detectors?

The Biomatrix mold monitor is more than the most technologically advanced smart home mold detector on the market. With the purchase of a Biomatrix device, your system will be monitored by a team of specialists, ensuring that your home is scanned for signs of trouble 24/7.

How do I find out where mould is coming from?

Mould often occurs because of condensation. It appears as pinpoint black spots, usually on the side surfaces of external walls, in corners and in poorly ventilated spaces, such as behind cupboards and wardrobes.

How do I find the source of moldy smell in my house?

To check your bedrooms for mould, look for visible signs on the walls, in corners, and behind furniture. Also try checking your dirty laundry, looking for leaks around the ceiling, pipes, and radiators, and for damp patches on your soft furnishings.

What are signs of mold sickness?

If you have a mold allergy, your immune system overreacts when you breathe in mold spores. A mold allergy can cause coughing, itchy eyes and other symptoms that make you miserable. In some people, a mold allergy is linked to asthma and exposure causes restricted breathing and other airway symptoms.

Do air purifiers help with mold?

Mold is an obvious health risk in any home, but investing in an air purifier can help limit your exposure. The best among them will ideally offer HEPA-level filtration, with this level of filtration being able to trap up to 99.97% of airborne particles down to 0.3 microns in diameter.

What does toxic mold smell like?

Black mold has an infamous, recognizable odor. Detecting this scent could be crucial in identifying a mold problem before it causes too much damage. Experts describe black mold as smelling musty—comparing it to rotting wood or leaves or wet, sweaty socks.

How do you test for mold behind drywall?

To tell if mold is inside your walls, professionals will take samples from the affected area through a swab test, bulk sampling (taking a piece of your drywall), and/or air test. After sample collection, they will take the samples to a laboratory for testing.

Does homeowners insurance cover mold?

Homeowners insurance doesn't usually cover mold damage or removal unless it's the result of a covered peril. If the mold in your residence was caused by something sudden or accidental, such as a bursting pipe or some other covered incident on your policy, you may be protected.

What happens if you smell mold but don't see it?

Bottom line: If you can't actually see mold, it's almost never a problem. The musty smell you ask about doesn't necessarily mean there are mold spores present, but can simply indicate you need more ventilation with fresh air.

Why does my groin smell like onions?

A strong onion-like odor may not always be a sign of an STI and could instead be caused by other factors like body odor, diet, or a forgotten tampon. Other causes of onion-like vaginal odor are: Poor hygiene: Excess discharge or improper cleaning after urination.

Can I test for mold myself?

Mold testing kits are available at most home improvement stores or online retailers, although not all tests are the same. There are some kits that only test for the presence of mold on surfaces, while others collect or grow samples of the mold that may be in your home.

How do I permanently get rid of mold in my house?

Spray the area with a mixture of water and vinegar - half water, half vinegar. Next, scrub to remove all traces of the mold. For removal of black and white mold, spray the area with the half water and half vinegar solution.

How do you know if your house has mold in the walls?

Check surfaces, especially your walls, for dark spots that look like stains or discolorations. Take note that mold can come in any color and texture. The most common colors are black and green and often look slightly furry, but they also tend to be wet and slimy.

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