How to safeguard your home against flooding in Ontario

(PaulMcKinnon/iStock)

Summary

• Ottawa faces flood risks from heavy rainfall, snowmelt, and its three major rivers.
• Prevent flooding by sealing cracks, cleaning gutters, and ensuring proper home landscaping.
• Install sump pumps, backwater valves, and inspect sewer systems to reduce water damage.

Ottawa is no stranger to the havoc wreaked by severe weather. We’ve all seen the images—flooded basements, soggy furniture, drywall reduced to mush and ruined personal belongings. As extreme weather events increase in frequency, these scenes become all too common. But why is Ottawa particularly prone to flooding?

Situated at the confluence of three mighty rivers, the Ottawa River, the Rideau River and the Gatineau River, our city is uniquely positioned in a flood zone. These waterways can swell significantly during heavy rainfall or rapid snowmelt, leading to widespread flooding. Numerous lakes dotting the region add to the complexity.

Understanding flooding

Ottawa’s weather, including heavy rain, snowstorms, and rapid thaws, can lead to sudden increases in water levels and overwhelm drainage systems. This can cause extensive damage to homes, businesses, and infrastructure, as well as emotional distress, financial hardship, and environmental impacts.

Ottawa has experienced significant flooding, notably in 2017 and 2019, resulting in extensive damage. These incidents highlight the need for effective flood management strategies. But here’s the thing—your home doesn’t need to be near a body of water to experience flooding. Malfunctioning municipal systems, internal plumbing issues, or severe weather can lead to flooding. With aging infrastructure and increased urbanization, homeowners must be aware of mitigation strategies to floodproof their homes.

The rising costs of flooding

In 2024, flooding and other weather-related events caused significant financial impacts across Canada. In Ontario, torrential rains in Toronto in July caused an estimated $940 million in damage. According to a StatsCan report, extreme weather is causing billions of dollars in damage and driving up insurance premiums. In Canada, insured claims costs reached $3.4 billion in 2022 and $3.1 billion in 2023, each more than 50 per cent above the yearly average. From 1983 to 2008, insurers paid an average of $400 million per year, but from 2009 to 2023, that average rose to almost $2 billion.

“These ‘once-in-100-years’ events are happening more frequently and are becoming more severe and costly,” the report states. From 2020 to 2023, homeowner insurance premiums in Canada increased faster than inflation.

Flooding in Ottawa and Gatineau

In 2024, the high water levels in the Ottawa and Gatineau regions were primarily due to a combination of significant snowmelt and heavy rainfall, which led to the Ottawa River exceeding its capacity, causing extensive flooding. About 250 houses and businesses were affected, prompting emergency measures, including the distribution of sandbags. This situation underscores the ongoing challenges in flood management and the importance of effective strategies to mitigate future events.

Protecting your home against flooding

Flooding isn’t just a concern during stormy seasons; it can strike at any time. By taking preventative measures, you can reduce the likelihood of damage, save on repair costs, and gain peace of mind.

Seal doors, windows and cracks in your basement

Cracks can develop in your basement floors and foundation due to thawing and freezing temperatures, improper grading, or expanding tree roots. These cracks can lead to water infiltration and structural issues. Cracks can also form due to shifting soil or poor construction. Leaving these unsealed can lead to water damage and structural problems over time.

To prevent this, inspect your foundation regularly. Minor issues can often be repaired from inside your basement. If needed, work with a professional to manage external repairs or excavation. Most cracks can be sealed from inside your home.

Clean and maintain gutters and downspouts

Gutter systems are essential for directing rainwater away from your home’s foundation and preventing long-term structural issues. By ensuring water is channelled correctly, you can prevent foundation cracks, leaks, and basement mould growth. A well-maintained system also protects your landscaping from soil erosion, shields your roof and siding from moisture damage, and helps prevent ice dams in colder climates by keeping melted snow away from the base of your home.

Regularly clean gutters and downspouts to prevent clogs. Downspouts must extend at least 1.8 meters from your foundation to keep water from pooling near your base. If your downspouts empty water across solid surfaces like driveways, the risk of refreezing or improper absorption increases. Additionally, ensure your downspouts do not direct water onto your neighbour’s property.

Downspout extensions provide a practical way to channel water toward lawns or gardens, ensuring safe, efficient dispersal. However, check local regulations, as some municipalities may restrict connecting extensions to underground drainage systems.

Improve landscaping

The ground around your home should slope away from the foundation. It’s recommended that the ground be 2.5 centimetres lower for every 30 cm you move away from your foundation. If the slope directs water toward your house, regrading the soil with stable materials such as clay can be an effective solution. Redirecting water flow will prevent pooling around your property and reduce the risk of damage during heavy rain or snowmelt.

If necessary, build your foundation on solid soil, such as clay, to ensure that heavy rainwater flows away from your home. Consider installing rain gardens to absorb runoff.

Install window well covers

Low-level basement windows are prone to water pooling and seepage. Window well covers can reduce the risk of water entering your home through these vulnerable points. Make sure the bottom of the well sits at least 15 cm below the window, and fill the window well base with gravel or sand to improve drainage.

Hire a certified plumber to check key systems

Your plumbing system plays an integral role in flood prevention. A certified plumber can check your home for potential weak spots and recommend upgrades.

Weeping tile is a pipe-shaped drain that runs along the bottom of a home’s foundation. Older homes may not have these, so consider having them installed. Weeping tiles can become clogged or collapse, and a plumber can assess their condition. Installing a cleanout port can make future maintenance easier.

Sump pumps move water from under and around your basement to the outside of your home. A sump pump is essential if your home has a high water table or isn’t connected to sewer laterals. It helps redirect water away from your home and is a key safeguard in high-risk areas. Ensure your sump pump works properly, especially in a flood-prone area.

Backwater valves prevent sewage from flowing back into your home. If sewage begins to move towards your basement, the valve will close, preventing sewer backup. Some municipalities offer rebates for installing backwater valves.

Sewer laterals are pipes that connect your home’s plumbing system to the city’s sewer system. They can become clogged with fats, oils, and grease, leading to a sewer backup. A plumber can use a camera to inspect your laterals and, if necessary, access the cleanout port to unclog them.

By taking these preventative measures, homeowners in Ottawa can better protect their homes from the increasing risk of flooding. Be vigilant, stay prepared and ensure your home is ready to withstand the challenges posed by severe weather.

• More articles about extreme weather preparedness

This advice is intended to provide general information only. It isn’t intended to provide legal or professional advice or to be relied on in any dispute, claim, action, demand or proceeding. CAA Insurance Company doesn’t accept liability for any damage or injury resulting from reliance on this information.