The City of Toronto’s Mandatory Downspout Disconnection Bylaw, which went through it’s final phase in December 2016, has added at least one task to homeowners’ list of things to do around the house.
While one of the bylaw’s main purposes was to reduce basements flooded due to overloaded storm sewers during heavy rainfall and snow melt, it has actually created a new risk of basement flooding. If you read the City’s Mandatory Downspout Disconnection page, most of it talks about how to make sure water drains away from your home.
Of course, if water doesn’t drain away and stays close to the house and its foundation, it could leak into your basement. So the City quite rightly advises that ‘water should flow away from a building’s foundations’. But the problem is that most homeowners aren’t landscape engineers.
Before the need to disconnect downspouts from sewers, the water that remained close to your home was minimal, which meant that the land around most homes was sufficiently sloped away from the house to handle any water that seeped in close to the foundation.
But with the downspouts disconnected, the amount of water absorbed by the ground around your home has increased. Even if you use downspout extensions and/or splash pads to disperse the water, it still could build up in higher quantities than before. And that build up is more likely in certain conditions.
Conditions like those Toronto has experienced so far in the winter of 2018 can lead to basement flooding. The extended period of below freezing temperatures we had after the holidays and through most of January was enough to thoroughly freeze the ground.
More recently, temperatures have risen and the built-up ice and snow on your roof melted. But the higher temperatures were not enough to completely thaw the ground. The result is that the water that drained off your roof ended up on ground that couldn’t absorb it very well.
If you look around your house, you might notice water pooling after a thaw. That tells you that the ground can’t absorb it all. Unfortunately, those water pools can get big enough to flow back toward your house. The heat of the home often keeps the ground from freezing immediately beside the home and the water finds its way into to ground right beside your foundation walls. And then it can leak into your basement.
Now you know why you should check around your house after a mid-winter thaw!