Why Does My Basement Have a Musty Smell?

Our basements tend to feel a bit damper than the rest of the house, and can often come with a musty smell. The reason for this is that mould and mildew can start to form when there is a build-up of moisture or dampness in the basement. 

Even basements that are used regularly can have a musty smell. A dark, damp basement is an ideal growing spot of mould and mildew and they don’t need much encouragement. Continue reading if you are wondering how to get rid of the basement smell.

What is that smell in the basement?

Unfortunately, there can be any number of smells permeating from our basements. The most common culprits are mould and mildew, but there are other reasons there can be a musty smell in the basement.

If you keep vegetables stored in your basement, rotting vegetables may be the source of the issue. It may be coming from an animal that got in and left its droppings. Mice and other rodents may enter your home and make a mess.

There could be a sewer leak from your pipes or even next door. Or there could be a blockage or damage in your floor drains, or even something blocking or living in your vents.

Mould and mildew are most common, however, and they can come from many sources. There could be a small leak from your pipes, your washing machine, or your freezer.

Mould can also start to grow on damp walls or floors. When small cracks appear in your concrete, moisture gets trapped and it isn’t long before the mould starts along with a bad musty odour.

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Why basements have an odour

Because basements are below ground they are prone to issues with moisture. Once the moisture starts to get in the small cracks or porous areas of concrete, mould can start to grow. It can happen from the inside, as well, causing a musty smell in the basement.

It can start with dampness building up on your walls in the basement. It can start from naturally occurring moisture that accumulates in a basement or from high humidity.

Humidity can come from a washroom, laundry room, or other appliances you have in the basement. These appliances can also have leaks adding more moisture to the air. There may be a lost piece of wet clothing that fell behind a machine or blocked floor drains that are not allowing excess water or moisture to dissipate. There could also be leaks behind the walls from broken pipes or taps. 

If you notice damp patches on the floor, the walls, or the ceiling, you may have a leak somewhere. It can come from drainage issues outside of the foundation, as water is not draining off and seeping in.

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Check for leaks in basement

If you’re still searching “how to get musty smell out of basement,” first you need to find out where the smell is coming from.

Leaks or pooling water are some of the most common reasons for a musty smell in the basement.


If you are wondering how to get rid of the musty smell in your basement, start by looking for cracks in the foundation. These can be very obvious or not at all. Check the walls, the floor, and the ceiling. Check behind appliances, furniture, or any items you may have stored in the basement.

All concrete has some cracks. Check the cracks you do find for moisture. You will see darker areas, damp patches, or even small drips of moisture falling out of them.

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Washers, deep freezers, dishwashers, fridges, or anything else you have in the basement that requires a water source could be the cause of this smell.

If you have a mini bar with a sink, fridge, and drainage, be sure to check for any leaks.


Broken or damaged pipes are a very common source of leaks.

Even pipes that are not damaged can have an excess amount of condensation around them, causing the humidity to rise and start dripping.

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Check the seals and frames of your basement windows. Water may be seeping in without you even realizing it.

The water could be causing the wood to rot which would also cause a musty smell in the basement.

Lower humidity level

Getting rid of the musty smell in the basement starts by bringing the level of humidity down. Once you have identified the reason your basement has a musty odour, it’s important to make the necessary repairs.Seal any gaps around your windows, taps or pipes in the walls, and repair or fill in any cracks that appear to have moisture. Some of these jobs you may be able to do on your own, but you are better off hiring a professional to make repairs.

Open your windows to air out the basement. This will help get rid of the musty smell in the basement. You can also use a dehumidifier to absorb and eliminate all the excess water and moisture in the air.

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Clean Up all mildew or mould 

You might still be wondering how to get rid of mildew smell in basement. You can use cleaning solutions to get rid of the musty smell in your basement like bleach, vinegar, or borax. Ideally, you want to have it professionally cleaned to ensure that the odour does not return.

Mould can make you sick and if you are susceptible to chemicals or live with respiratory concerns, it’s crucial that you hire a professional cleaning team that has experience cleaning mould and mildew.

Steps to Eliminate Musty Smell

Once you have had the mould professionally cleaned, it’s important to keep it that way. It’s a good idea to have your basement and your foundation regularly inspected to stay ahead of these issues. 

Make sure to keep your pipes and appliances in tip-top shape and use a dehumidifier in the basement whenever possible. You can use natural air fresheners like candles, essential oils, or incense to help deodorize your basement too. Call a professional to come in and fix any cracks, or leaks, or fix or replace any damaged or old pipes.

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Contact Us 

Harmony Basements is an award-winning company that specializes in basement services in the GTA for over 20 years. Contact us today, and we can answer any questions you may have about how to get rid of the musty smell in your basement.