Water Seeping Through Basement Floor in Toronto Basement


Do you have water seeping through your basement floor?  Many homes in Toronto do, this is largely due to the age of the homes here as well as the fact many parts of Toronto sit on top of high water tables from the many underground rivers that flow under it.

Basements are an inevitable target for water. That’s because they’re underground, and there’s almost always moisture somewhere nearby waiting to get into your basement through a crack or seam.  If you think of an inground swimming pool, that’s what a basement is, except it’s trying to keep the water out instead of in. While a well-built, properly water-proofed basement could remain dry almost indefinitely, many others fail, because the foundation was not properly waterproofed in the first place or the repair job was more of a bandaid rather than a long-term waterproofing solution.

Water Leaking into Basement Floor

Diagram of water seeping through basement floor


Reasons for the Problem

There are several causes for wet basements. These can occur simultaneously. For purposes of simplicity we separate them below.

  • Ground Water – This either filters down from rainwater accumulating above, or through horizontal strata in the ground. If your basement damp problem worsens in rainy months, this could be a likely cause.
  • Backed-Up Sewer Pipes – Many older Canadian homes still have storm water run-offs connected to their sewer lines. If your damp problem traces to an overflowing toilet, then you need to modify your drainage system.
  • Leaking Pipes – Some plumbers have a habit of concealing pipes in walls. All pipes have to pass through walls anyway. If your floor stays damp throughout the dry season, then you should call in a plumber to do some tests.

Your problem will most likely be caused by rain water filtering through the earth surrounding your foundation, and coming up against your basement walls and floor where the hydrostatic pressure may be quite intense. If you believe this is the case, your solution depends on a combination of prevention and cure to stop your basement leaks.  When there is too much pressue trying to get into your basement, simple waterproof paint or sealants tend not to work very well.

Before beginning, first tape a sheet of plastic over your basement floor making sure to seal the edges and any joints. Lift it up two weeks later. If the floor’s still damp the water’s rising through it. If not, the problem could be in your walls and you need to look elsewhere.

Preventing Water From Seeping Into Your Basement

There’s little you can do about groundwater travelling horizontally through the ground. You have to deal with it when it arrives, usually with an interior weeping tile system. However if it’s filtering down from the surface overhead, then that’s a completely different matter. Investigate the following:

  • How effectively is the rainwater discharged from your roof? Is it lead away through channels, or pooling in the vicinity of the basement?  Proper runoff from downspouts can help keep water away from your foundation.
  • Does the ground slope steadily away from your home allowing a gentle yet effective runoff?  Grading the spoil to run away from your foundation will help keep water away form your foundation.
  • Turn off your water supply at the entrance to your property. Does the meter stop when everything’s turned off onside? If not there could be a leak in your supply main that’s filtering underground.


Wait a few weeks after implementing the above solutions, preferably during a dry period to let the ground dry out. If there’s still moisture rising through your basement floor you have two options open to you:

  • Remove the surrounding earth and install a weeping tile system that stops the ground water in its tracks.
  • Install a french drain just inside the basement walls, and pump the water to the outside where it can trickle away harmlessly

Water entering your basement through foundation cracks is hardly a DIY project. The work is onerous, and you need protective gear to avoid infections from mold and water borne illnesses.  Besides, is this really the way you want to spend a month of weekends? If you live in Toronto or the surrounding GTA, Nusite Waterproofing can come to your home and conduct a free in-home inspection of your problem and provide you with a written quote.  We can also go over all available options to fix your basement leaks so you can make an informed decision.  Contact us today to get started.

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Waterproofing & Foundation Specialists at Nusite Contractors Ltd
As a family-owned waterproofing and foundation repair business with over 30 years of experience in Toronto, we are proud of our work and stand by it with a full warranty. We’re a service company, working for you. We make sure our customers understand the entire building and repair process, and ensure that our work is done properly and made to last.
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