What’s the Difference Between Sewer Backup and Overland Flood Coverage?

Water damage is one of the most common and costly insurance claims in Canada, and not all water is treated the same. If it enters your home from above ground or from below, it may trigger different types of insurance protection—or none at all if you’re not properly covered.

This matters when your basement floods or a storm overwhelms your neighbourhood. You might think about this the next time heavy rain is in the forecast or your sump pump is working overtime.

The Key Difference: Where the Water Comes From

The main distinction between sewer backup and overland flood coverage lies in how the water enters your home. While both involve flooding, the cause and entry point determine which coverage applies.

Sewer backup coverage protects you from water that flows into your home through internal plumbing, such as floor drains, toilets, or sinks, typically caused by an overloaded municipal sewer system or sump pump failure.
Overland flood coverage protects you from water that enters your home after collecting above ground due to rain, snowmelt, or river overflow.

Coverage Type	Source of Water	Typical Entry Point	Covered Events
Sewer Backup	Municipal sewer, septic, sump systems	Through drains or fixtures	Blocked sewer lines, sump failure, backups
Overland Flood	Surface water from rain or snowmelt	Through doors, windows, cracks	River overflow, pooling rainwater

Note: These two coverages are often offered as separate endorsements and are not included in standard home or condo policies. You need to request them specifically.

Why You Might Need Both

Water damage does not always follow neat categories during severe weather. A major storm can overwhelm the stormwater system, back up your basement drain, and cause surface water to pool against your home—all at once.

Without both sewer backup and overland flood coverage, your insurer may only pay for part of the damage, or deny your claim altogether if the water source is not covered by your policy.

Tip: Consider bundling both protections as part of a comprehensive water damage endorsement. This simplifies your coverage and may lower your premium compared to buying them separately.

How to Determine Your Risk

Older neighbourhoods often have combined storm and sewer lines, increasing backup risk
Homes at the bottom of a hill or near a river are more exposed to overland flooding
Poor drainage, blocked gutters, or low window wells all increase vulnerability

Caution: Some insurers place limits on sewer backup or flood claims in high-risk areas, or require specific mitigation steps like sump pumps or backwater valves to qualify for full coverage.

Better Protection Starts with Clarity