There’s a big difference between a room that’s messy and a room that smells off. You can tidy up all you want, but if there’s a musty smell lingering in the air, the room never actually feels clean. It’s that damp, stale, basement-like odor that hits you the moment you walk in — and unfortunately, it tends to get worse over time if you ignore it.
I lived with a musty guest bedroom for months. I tried masking it with candles and air fresheners, which worked for about an hour before the smell came right back. It wasn’t until I started looking for the actual cause that I realized the window had a tiny leak that was letting moisture in behind the curtain every time it rained. No amount of scented candles was going to fix that.
Musty smells are almost always caused by moisture and the mold or mildew that grows because of it. To get rid of the smell permanently, you have to eliminate the moisture source, clean up any existing mold, and then freshen the air. This guide walks you through each step.
What Causes Musty Smells?
Understanding the cause helps you find the right solution. Musty odors are typically caused by:
- Mold and mildew — The most common cause. These fungi thrive in damp, warm environments and release that characteristic earthy, stale smell.
- High humidity — Rooms with poor ventilation or excess moisture in the air develop that damp smell over time.
- Water leaks — Even small, hidden leaks behind walls, under floors, or around windows create the perfect environment for mold.
- Condensation — Poorly insulated windows or pipes that sweat in humid weather create moisture that leads to odors.
- Poor air circulation — Rooms that are closed up for long periods trap stale air and moisture.
- Wet items left sitting — Damp towels, clothes, or rugs that don’t dry properly develop a musty smell quickly.
The key thing to remember: musty smells are a symptom, not the problem itself. If you only treat the smell and not the cause, it will come back.
Step 1: Find the Source of the Moisture
Before you do anything else, track down where the moisture is coming from. This is the most important step. If you skip it, the smell will return no matter how much you clean.
Check These Common Problem Areas
Windows
Look for condensation on the glass, water stains on the sill, or peeling paint around the frame. Run your hand along the bottom of the window sill — if it feels damp, you may have a leak.
Walls and Ceilings
Look for water stains, bubbling paint, or soft spots. Pay attention to corners and areas near the ceiling, which is where leaks from the roof often show up first.
Under Sinks
Check both kitchen and bathroom cabinets for water stains, warped wood, or a damp smell. Small leaks under sinks are easy to miss because you don’t see them every day.
Around Appliances
Check behind and under the refrigerator, washing machine, and dishwasher. A slow drip from a water line can go unnoticed for a long time.
Near Plumbing
Look at exposed pipes in the basement, under sinks, and near the water heater. Check for corrosion, green marks on copper pipes, or water stains on nearby surfaces.
The Floor
Especially in basements and ground-level rooms. Look for damp spots, water stains, or areas where the flooring is warped or lifting.
The Closet
Closets on exterior walls can develop moisture problems because the inside wall is warm and the outside wall is cold, which creates condensation. Check for damp walls, musty clothes, or a stale smell when you open the door.
What to Do If You Find a Leak
If you find an active leak, fix it before you do anything else. This might mean:
- Replacing a worn washer in a faucet
- Re-caulking around a window or tub
- Tightening a loose plumbing connection
- Calling a plumber for a hidden pipe leak
- Repairing a roof leak
If the leak is significant or you can’t find the source, it’s worth having a professional take a look. Water damage gets more expensive to fix the longer it sits.
Step 2: Clean Up Any Visible Mold or Mildew
Once you’ve addressed the moisture source, clean any mold or mildew you can see. Even small patches contribute to the smell.
On Hard Surfaces (Tile, Glass, Metal)
Mix equal parts white vinegar and water in a spray bottle. Spray the affected area and let it sit for 15 minutes. Scrub with a brush and rinse with water. Vinegar kills about 82 percent of mold species and is safer than bleach for most surfaces.
On Walls and Ceilings
For painted surfaces, use a mixture of warm water and mild dish soap. Scrub gently with a sponge — don’t saturate the wall. If the mold has penetrated the paint, you may need to repaint with a mold-resistant paint after cleaning.
On Wood
Wipe the area with a cloth dampened with vinegar solution. Don’t soak the wood. Dry it thoroughly afterward. If the wood is soft or crumbly, the rot has gone too deep and the affected section may need to be replaced.
On Fabric and Upholstery
For washable fabrics, wash in hot water with detergent and a cup of vinegar. For upholstery that can’t be removed, spray lightly with vinegar and let it dry in the sun if possible. Test an inconspicuous area first to make sure the vinegar doesn’t discolor the fabric.
When to Call a Professional
If the mold covers an area larger than about 10 square feet, or if it’s in your HVAC system, behind walls, or in other hard-to-reach places, it’s best to hire a professional mold remediation company. Large mold infestations can cause health problems and need specialized equipment to remove safely.
Step 3: Dry Out the Room
Mold and mildew can’t grow without moisture. Once you’ve cleaned the visible mold, focus on drying out the room thoroughly.
Open Windows and Doors
If the weather is dry and not too humid, open windows and doors to let fresh air circulate. This is the simplest way to dry out a room and it costs nothing.
Use Fans
Position fans to blow air across damp areas and toward open windows. Box fans or oscillating fans work well. Keep them running for several hours or even a full day if the room is very damp.
Run a Dehumidifier
If you live in a humid climate or the room doesn’t have windows, a dehumidifier is your best bet. These devices pull moisture out of the air and collect it in a tank that you empty periodically. A good dehumidifier can drop the humidity in a room from 70 percent to 40 percent in a matter of hours.
Aim for indoor humidity between 30 and 50 percent. Anything above 60 percent encourages mold growth.
Use Desiccants for Small Spaces
For closets, cabinets, or other small enclosed spaces, moisture-absorbing products like DampRid or silica gel packets can help. They don’t need electricity and work quietly to pull moisture from the air. Replace them when they’re full.
Heat the Room
If it’s cold outside, turning up the heat can help dry out a room. Warm air holds more moisture than cold air, which means it can absorb dampness from surfaces. Just make sure you also have ventilation — otherwise you’re just moving the moisture around.
Step 4: Remove the Lingering Odor
Once the room is dry and the mold is cleaned up, you may still have some lingering smell. Here’s how to get rid of it.
White Vinegar
Vinegar is one of the best odor neutralizers. Place bowls of white vinegar around the room and leave them for 24 to 48 hours. The vinegar smell will be strong at first, but it dissipates as it absorbs the musty odor.
You can also wipe down hard surfaces with a vinegar solution to remove any remaining odor-causing residue.
Baking Soda
Baking soda absorbs odors naturally. Sprinkle it on carpets, rugs, and upholstery, let it sit for a few hours or overnight, then vacuum it up. You can also place open boxes or bowls of baking soda in closets, cabinets, and corners.
For persistent smells, make a thick paste of baking soda and water, apply it to the affected area, let it dry completely, then vacuum or wipe it away.
Activated Charcoal
Activated charcoal is extremely effective at absorbing odors. You can buy it in bags or small containers designed for odor removal. Place them around the room, especially in areas that tend to stay damp. They work for several months before needing to be replaced.
Coffee Grounds
Dry, used coffee grounds can absorb odors. Spread them on a baking sheet and let them dry completely, then place them in bowls around the room. They add a mild coffee scent while absorbing the musty smell.
Fresh Air and Sunlight
If possible, take washable items outside and let them sit in direct sunlight. UV rays kill mold and bacteria, and fresh air naturally deodorizes fabrics. This works well for pillows, cushions, rugs, and clothing.
Step 5: Prevent the Smell from Coming Back
Once you’ve gotten rid of the musty smell, take steps to keep it from returning.
Improve Ventilation
- Run exhaust fans in the bathroom and kitchen when showering or cooking
- Open windows regularly when the weather allows
- Leave closet doors slightly open to allow air circulation
- Don’t push furniture tight against exterior walls — leave an inch or two for air to flow behind them
Control Humidity
- Use a dehumidifier in damp rooms, especially basements
- Run the air conditioner in summer to reduce indoor humidity
- Fix leaks promptly — even small ones
- Vent clothes dryers to the outside, never indoors
- Don’t hang wet clothes to dry indoors if you can avoid it
Clean Regularly
- Vacuum and dust weekly to remove mold spores and dust that can trap moisture
- Wash bathroom rugs and shower curtains regularly
- Clean under sinks and behind appliances periodically
- Check for leaks monthly as part of your home maintenance routine
Use Moisture Barriers
- Place a moisture barrier on the floor of closets that are on exterior walls or in basements
- Use shelf liners in cabinets under sinks
- Keep items off basement floors using shelving or pallets
Common Rooms That Get Musty and Why
Some rooms are more prone to musty smells than others. Here’s why and what to watch for.
Basements
Usually the dampest room in the house because they’re below ground level. Water seeps in through foundation cracks, and poor ventilation traps moisture. A dehumidifier is almost always necessary in a basement.
Bathrooms
Constant moisture from showers and baths makes bathrooms a prime spot for mold and mildew. An exhaust fan that runs during and after showers is essential.
Closets
Enclosed spaces on exterior walls with no ventilation are mold magnets. Leave doors slightly open and avoid packing clothes too tightly.
Laundry Rooms
If your dryer isn’t vented properly, all that moisture from wet clothes goes into the air. Check your dryer vent regularly and make sure it’s not blocked or disconnected.
Kitchens
Cooking releases moisture into the air. Boiling water, running the dishwasher, and washing dishes all contribute. Use the range hood fan when cooking.
Frequently Asked Questions
Will the musty smell go away on its own?
No. If the smell is caused by mold or moisture, it will persist or get worse until you address the root cause. Masking it with air fresheners or candles only covers the odor temporarily.
Can musty smells make you sick?
Prolonged exposure to mold and mildew can cause respiratory issues, headaches, and allergic reactions, especially in people with asthma or mold allergies. If you notice health symptoms that improve when you leave the house, mold could be the cause.
Is bleach or vinegar better for killing mold?
Vinegar is actually more effective than bleach for most household mold. Bleach only kills mold on non-porous surfaces and doesn’t penetrate porous materials like wood or drywall. Vinegar penetrates porous surfaces and kills the mold at the root. Plus, bleach releases harmful fumes and can damage some surfaces.
How long does it take to get rid of a musty smell?
It depends on the severity. A mild smell in a well-ventilated room might clear up in a day or two after cleaning and airing out. A strong smell from a significant mold problem could take a week or more, especially if you need to dry out the room and replace affected materials.
Do air purifiers help with musty smells?
Yes, especially those with HEPA filters and activated carbon. HEPA filters trap mold spores from the air, and activated carbon absorbs odors. An air purifier won’t fix the moisture problem, but it can improve air quality while you address the cause.