Handling Pest Control Issues After a Flood

Flood is a common and costly disaster. They may occur after a heavy and steady rainfall or when winter ice thaws. In Canada, the warming temperatures by spring carry heavier rainfalls and quicken the melting of ice, increasing the risk of flooding. It is a threat both to your property and your health. But while you may be focusing on rebuilding your home after the flood, there could be another issue brewing that may add to your troubles — unwanted pests.

Just like humans, animals will flee their homes and search for drier and higher grounds during floods. Unfortunately, homes and other buildings offer them safe refuge. Days and weeks after the event, pest infestation can be a serious problem, hampering your full recovery and rehabilitation.

So how do you keep your property pest-free after a flood? Here are some things you need to know.

Pests That Emerge After Floods

When returning to your home or business post-flood, it is important to stay out of flood waters and keep an eye out for the following pests:


Ants can float in a flood until they find dry land

After a flood, you may have to deal with ants. Flood waters can rush into and inundate ant colonies, forcing them to escape quickly to find a new habitat. They can cling together in tight groups and float in a flood until they find dry land. Once they find dry land, such as your house, they will then try to rebuild their colonies. Suddenly, you may find mounds appear where there was nothing before.


No other pest thrives better after heavy rains and floods than a bloodthirsty mosquito. Mosquitoes breed in stale, standing water, and larvae only take weeks to become adults. Stagnant waters will be everywhere after a flood. As a result, their population can quickly explode.

In addition to their irritating bites, mosquitoes are infamous for their ability to carry diseases. Annually, they kill more people globally than any other known insects.


Similar to ants, termites are underground-dwelling creatures. The flood can submerge their dwellings and drown them if they don’t flee and build a new home elsewhere. Standing water in your crawl space and wet insulation, as well as damp woods, are good places for them to resettle.

If your home had been treated for termites before, flood water can also compromise the termite treatment barrier. You may have to re-apply termite protection materials to keep your home safe.


Cockroaches breed fast under wet and humid conditions

Cockroaches are naturally drawn to humid and wet environments. These are perfect breeding grounds for these insects, which means a home damaged by flooding becomes a free-for-all. Another terrible thing about cockroaches is that they breed fast. They will hide in the nooks and crannies of your home. You may not notice them for weeks at first, but by the time signs of them appear, chances are they will have already multiplied exponentially.

Rats and Mice

Rodents, like rats, mice, and even raccoons, are known to be the worst invaders. Many rodents like to live underground. As soon as flood waters penetrate their homes, they will find a higher and dryer place for protection and shelter.

Unlike insects such as flies and cockroaches, rats and mice will find a safe nesting place first and search for food later. Unfortunately, the only places that are usually warm and dry during floods are houses. Rodents will try any possible modes of entry to get inside, including climbing, squeezing, and chewing their way through.

Worse still, after they’ve found ideal refuge in your home, they will then raid your cupboards and bins for food, adding to an already miserable situation.

House Flies

Flood isn’t only pure water. Flooding also causes sewers and sewage treatment facilities to overflow. Not only that, but it can also carry dead animals, garbage, food, and other organic matters, which are all appealing to flies.

Even after it subsides, the wet wood starting to rot and decay, or the bad odour from the spoiled items in your refrigerator after it loses power can still draw in flies into your home.

Snakes, Reptiles, and Other Wildlife

As much as possible, animals like to live in the wild. But heavy floods too close to home can also displace them and force them to travel into unfamiliar areas.

Reports of snakes, reptiles, and other wildlife found in unusual places after a flood is not so rare. Wildlife experts even warn that as we construct more buildings and encroach into their natural habitats, it will be more usual for humans to cross paths with animals.

How to Control Pests After a Flood

Pest problems can already compound on the existing difficulties and challenges associated with post-flood recovery. Consider the following steps to mitigate the pressure brought along by pests in your home after flooding:

Inspect Premises for Damage


As soon as the floodwater subsides, it is important that you inspect the structure first for any sustained damage to determine if it’s already safe to return home and also identify which areas need fixing or replacing.

Besides that, a flood may have cracked a wall or broken a window, providing pests access to your home.

Secure Any Access Points
If the flood destroyed certain areas, cover them up as soon as possible. Keep entrances covered with plywood or mesh screens because while groundwater may have already receded, sewers could still be flooded. Pests may still be looking for a place to stay in, and closing all entry points makes it harder for these opportunistic tenants to find access to your property, causing them to give up and find an easier target.

Control Moisture
Warm, moist environments make the best breeding grounds for pests, and floods can catalyze these conditions. One of the best ways to prevent an infestation in your home post-flood is to control moisture and regulate humidity. Fans are helpful tools to cool your home and dry your rooms. You can also invest in a dehumidifier if humidity is a problem.

Don’t forget to remove any areas or items that hold standing water, such as bottles, cans, tires, pots, and buckets. Any place that holds half-an-inch deep water is enough for mosquitoes to breed.

Locate Sources of Trash and Organic Matters

Flood can leave a pile of trash

All pile-up of trash and organic matters are a good source of both food and shelter for these pests. Rodents, cockroaches, and flies, take advantage of these available resources to flourish. It’s better to place them inside sealed bags and tight-lid containers or dumpsters.

If you are to deal with animal carcasses, immediately call your local animal care and control services, after putting them inside a plastic bag. Also, make a note and share the information with your pest management provider to make treatment efforts more effective.

Create an Insecticide Barrier
Applying an insecticide barrier around your home after floodwaters have receded will prevent pests from invading your place. It is recommended to spray the following areas:

  • Up and out from the foundation
  • Around your house’s outer perimeter
  • Around door and window frames
  • Along cracks and crevices
  • Where utilities enter the home

Clean and Sanitize
Most importantly, clean and declutter your home after the flood. The goal is to remove and dry all water-soaked and water-compromised objects and materials from your home. Sanitize around and underneath furniture, fixtures, and appliances to get rid of any dirt and excrements left by the floodwaters.

Get Rid of the Pests

Protect your home from pest infestation after a flood

Spring is coming and so is the risk of flood and pest infestation. While we cannot control the season, we can choose how to tackle these threats. For the best pest control and protection, call the professionals.

JDM Pest Control has been offering safe, effective, and eco-friendly pest control services in the Greater Toronto Area for over 20 years.

If you have any questions and concerns about post-flood pest control, call our hotline (416) 729-3568 for a free assessment now!