Fighting Mold in Your Rental Property

by | May 9, 2011 | Rental Property Management Tips

Mold growing inside a rental property can trigger health concerns for tenants and cause damage to surfaces.

Mold only grows where it finds moisture. High moisture levels can be the result of water coming in from the outside, through the floor, walls or roof, or from plumbing leaks.

What’s going on inside can also affect the moisture levels. Moisture can be produced by the people living in the home through daily activities like bathing, washing clothes or cooking. 

Moisture accumulates within the home when there is not enough air circulation to expel it, like from a kitchen exhaust fan vented into the attic.

Removing mold permanently can be a daunting task because trouble spots tend to come back again if the moisture problem remains. Preventing mold is the best option for lowering the repair costs and keeping tenants happy and safe.

The Canadian Mortgage and Housing Corporation has these suggestions for mold-proofing the most susceptible areas of your property:

Basement or crawl space

Reduce the amount of clothes, paper and furnishings stored in the basement.

Discard badly damaged materials – the mold spores may grow back. 

Eliminate clutter to improve air circulation. Only washable items should be stored.

Dehumidify the basement during the warm months.

Avoid carpets on slab-on-grade or below grade floors.

Periodically clean the drain in your basement floor. Use half a cup of bleach, let it stand for a few minutes, then flush with plenty of water. Keep the drain trap filled with water.

Avoid standing water. Keep sump pits covered (you can use plywood wrapped with plastic).

Regularly clean and replace furnace filters. Use a pleated one-inch filter, not a coarse filter.

If you have a heat recovery ventilator (HRV), clean the filter inside the HRV often.

If you notice molds or signs of dampness, such as water on your windows or wet spots elsewhere, do not humidify. Disconnect furnace humidifiers that are no longer used.

If you have electric baseboards, vacuum the units, or have a professional clean them for you.

Laundry areas

Check that your clothes dryer exhausts to the outside.

Instruct tenants to:

Remove lint every time they use the dryer.

Avoid hang-drying  laundry indoors.

Dry the laundry tub and washing machine after each use.


Check the bathroom fan to make sure it exhausts to the outside.

Instruct tenants to turn the bathroom fan on when they shower, and keep it running for a few minutes afterwards.

Encourage tenants to take short showers.

Keep surfaces that get wet, such as the walls around the bathtub and shower, clean and dry.

Remove carpeting in bathrooms and replace with hard-surface flooring.

Check for water leaks.

Keep drains in good shape by removing debris from them.  To clean a drain, pour a handful of baking soda into it.  Add a cup of vinegar.  Put the plug in the drain.  Let the vinegar and baking soda work for about 20 minutes.  Run fresh water into the drain.

If the drain is still clogged, use a small plumbing snake.


If the fan over the stove exhausts outside, instruct tenants to use it when they cook.

Minimize open boiling.

Keep your drains in good shape. Follow the steps in the Bathrooms section above.

There’s a drip pan at the back of the refrigerator. Pull the refrigerator out to clean the drip pan. At the same time, vacuum dust from the coils at the back of the refrigerator.

Check under the kitchen sink to make sure there are no leaks.

Instruct tenants to take out the garbage daily to prevent odours and spoiling.

Closets and bedrooms

Encourage tenants to get rid of clothes and other stored items that they don’t use. Keeping closets and bedrooms tidy makes it easier for air to circulate — and harder for mold to grow.

Other parts of the home

A dehumidifier helps to reduce moisture in the home during the warmer months. Have tenants close the windows when the dehumidifier is running.

Ask tenants to have visitors take off their shoes.

Tenants should vacuum often. If you supply a vacuum cleaner, try to get one with a HEPA filter.

Instruct tenants to clean hard floors with a damp mop.

Do not allow tenants to bring in furniture, clothing, books etc. that have been stored in a moldy place.

Cut down the number of potted plants in the house—soil is a good place for mold.


Regularly check the condition of the roof and exterior finish for any places where water might enter.

Make sure that eavestroughs and downspouts are connected and working properly and that they are free of debris.

Install downspout extensions to lead water away from the building.

Deal promptly with any problems that you find.

This post is provided by Tenant Verification Service, Inc., helping landlords reduce the risks of renting with fraud prevention tools that include Tenant Screening, Tenant Background Checks, (U.S. and Canada), as well as Criminal Background Checks, and Eviction Reports (U.S. only).

Click Here to Receive Landlord Credit Reports.

Disclaimer: The information provided in this post in not intended to be construed as legal advice, nor should it be considered a substitute for obtaining individual legal counsel or consulting your local, state, federal or provincial tenancy laws.

Property management software for Canadian Condos.

Property Boss

Property management software for single family, multifamily, and student housing.


Screening services for property managers and landlords. Select a market below.