How to prevent flooding in your home and basement: Expert tips as heavy storms hit Canada this spring

Yahoo

05-04-2025

As parts of the country brace for severe thunderstorms and heavy winds, many Canadians are on high alert for signs of flooding in their homes and basements. According to a recent Léger poll conducted on behalf of Allstate Canada, 10 per cent of Canadians with basements have experienced basement flooding. As we prepare for heavy rainfall and a wet spring, it might be the perfect time to reassess whether you have all the safeguards in place to protect your home from water damage.
'The spring thaw is the worst time of year for flooding by far,' says Jake Allemang, founder and president of Mechanical Flood Protection, which operates in Ontario and Nova Scotia. 'We rely on the roots from trees and foliage, as well as the ground itself, to absorb the water when it rains hard. It can't do that when the ground is frozen.'
According to Allstate Canada, the average cost to repair a water-damaged basement has risen nearly 20 per cent over the past five years — approximately $40,000 reports to the Government of Canada. Luckily, Allemang says there are many steps you can take to protect your home from basement flooding. Below, he shares what you can do to prevent water damage.
There are two main causes of flooding that aren't related to plumbing concerns:
Overland
When water crosses land (often from a river or stream) and enters a home, that's called overland flooding. 'It typically happens during major weather events like a hurricane or very bad rainstorm,' says Allemang.
Groundwater
'Groundwater flooding is more sinister than overland flooding because, essentially, the water table rises over time and becomes unable to absorb water,' says Allemang. 'Then it creates hydrostatic pressure on your basement floor or walls.'
Issues with plumbing, such as broken or burst pipes, clogged drains or appliance malfunctions, can also cause flooding. In older communities with combined sewer infrastructure, sewer backups can be a problem, too.
'If there's a heavy rainstorm, it could overwhelm the system,' says Allemang. The result is the contents of the sewer flowing backward into people's homes.
Even if you have flood insurance, you won't get back the priceless items or the time and space you lose during repairs. To reduce the chance of water damage in your home, particularly during the spring thaw, there are several steps you can take.
Keep your eavestroughs clear: Regularly clean leaves (and ice) out of your eavestroughs so they can effectively collect water from your roof.
Purchase downspout extensions: Direct rainwater away from your foundation by adding extensions to your downspout. 'It's an easy trick that only costs about $10 for 10 feet,' says Allemang.
Place water sensors in basement corners: Place sensors in the corners of the basement and near the sewer or water-main entrance. While sensors won't protect you from flooding, they will sound an alarm at the first sign of water, giving you a chance to retrieve important items.
Sump pump with a backup power source: Move groundwater away from your home and keep the water table low, even during a power outage.
Backwater valve: Prevent sewer backflows with a valve that automatically closes if it senses fluid moving the wrong way.
Smart leak detector: Automatically scan your plumbing system each day and, in the case of a leak, cut off the water supply. Turn it back on via an app.
Allstate Canada's poll found that many homeowners use their basements to store expensive and priceless items: a fridge or freezer (55 per cent), skis and bikes (41 per cent), photo albums (40 per cent), entertainment equipment (32 per cent) and important financial, legal or tax documents (28 per cent).
Even if you've installed flood prevention systems, there are other ways to help protect your items:
Keep things elevated by placing them on shelves or hanging them on the wall
Store items in plastic bins, not cardboard boxes
Move your most important objects or bins upstairs
Wet spots are a sign that you could be at risk for flooding. 'You'll start noticing moisture spots on the floor, especially where the floor meets the wall,' says Allemang.
Before too long, you'll want to have a flood prevention or waterproofing company come in to assess your options, whether they involve installing or repairing drainage systems, redirecting water, sealing cracks or re-grading the landscape around your home.
In the interim, use a dehumidifier to keep the space dry.
Basement flood protection subsidies may be available at the municipal level (like in Toronto), so it's worth doing your research. However, 'I have installed 296 sump pumps in the last year, and not one of those customers has ever gotten any kind of subsidy as far as I know,' says Allemang.
Flood insurance is often an optional add-on. Read your home insurance policy carefully and discuss additional coverage options with your insurance provider.
Insurance companies will often provide a discount on coverage if you have flood protection devices installed. 'We've seen savings of five to 15 per cent,' Allemang says.
If you get to the point where your home is flooding, there isn't a ton you can do.
Shut off your water main: If you're able to safely access the shut-off valve (it's often located near the water meter), turn off your water.
Stay out of the water: Electrified water can cause severe electric shock, while contaminated water can result in illness.
Call a remediation company: They can safely pump out the water and use fans and dehumidifiers to reduce damage.