The 100 Year Storm - It's Has Happen 10 times starting May 12, 2000

 If Your Basement Took on Water This Week, You're Not Alone — And You're Not Out of Options

You didn't imagine it. What hit Toronto on September 2nd wasn't a normal summer rain. Parts of the city saw over 100 millimetres come down in a matter of hours — the kind of rainfall the city itself has called a once-in-a-century event. The Don Valley Parkway turned into a river. Tens of thousands of homes lost power. And in basements across Toronto, Scarborough, North York, Etobicoke, and East York, water came up through drains, around foundations, and into rec rooms, laundry rooms, and storage spaces that people had spent years building into real parts of their homes.

If that was your basement, we're not going to tell you what you should have done. We're not going to say we told you so. You're dealing with enough right now — soaked carpet, ruined boxes, maybe drywall that must come out, maybe a claim you're not sure how to file. That's a hard week. We see it, and we're sorry you're going through it.

What we want to do instead is something more useful: help you understand what actually happened, why it happened to some homes and not others, and what real, concrete options exist so this doesn't happen to you again — without the scare tactics, without the pressure, and without pretending there's a one-size-fits-all fix.

What actually happened on September 2nd

This wasn't a case of a few clogged eavestroughs or someone forgetting to check their sump pump. Environment Canada and city officials described this storm as extreme — some neighbourhoods received close to a month's worth of rain in a single afternoon. Toronto Fire responded to over a thousand calls for service. Water rescues happened on flooded roads. Trees came down, power lines came down, and the stormwater system — the pipes and sewers that are built to handle a certain amount of rain per hour — simply could not keep up with what fell.

Here's the part that matters for your basement specifically: when city sewers get overwhelmed that fast, water doesn't just sit in the street. It looks for the lowest point to go, and in a lot of homes, that lowest point is your basement floor drain. If your home doesn't have a backwater valve, or has one that's aged out, undersized, or wasn't installed to code, that overwhelmed municipal system can push water backward through your own pipes and into your house. That's not a reflection on you as a homeowner. Most people have never been told this is even a risk until the day it happens.

This wasn't a one-off

We wish we could tell you this kind of storm is rare enough that it's not worth thinking about again. The honest answer is that it's happening more often, and city data backs that up — Toronto's own planning documents already account for rainfall intensities getting worse over the coming decades, not better. Basement flooding events tied to overwhelmed sewers have hit this city multiple times in the last several years alone, each one described at the time as unusual, each one followed by another.

We're not saying this to scare you. We're saying it because the single most common thing we hear on site, standing in a flooded basement, is "I didn't think this would happen to us." We'd rather you hear it from us in a calm moment than learn it the hard way a second time.

This isn't the first time — and the record shows it

Toronto doesn't have just one bad storm story. It has a pattern, and it's documented:

May 12, 2000 — a major basement-flooding event still referenced in the city's own flood-risk engineering data.

August 19, 2005 — a storm severe enough that the city's current city manager pointed to it directly as the closest historical comparison to this year's event.

July 8, 2013 — Toronto's most damaging storm on record at the time. Pearson Airport logged 121mm of rain, breaking a record set by Hurricane Hazel back in 1954. A GO Train full of passengers was stranded for hours, 300,000 homes lost power, and total damages were estimated near $1.5 billion.

2017 and 2019 — back-to-back years of record-high Lake Ontario levels flooded the Toronto Islands for months at a time.

August 2018 — officially classified a 100-year storm. At the time, Toronto Life reported it was the sixth 100-year event the GTA had seen in roughly two decades.

July 16, 2024 — flooded Union Station and the Don Valley Parkway, with insured damages later reported near $990 million.

August 2024 — a second major storm the same summer broke the 2013 rainfall record.

September 2, 2026 — this week's storm. City officials confirmed it met the threshold of a 100-year event and said Toronto Water had never seen that much rain fall across the entire city at once.

That's at least three major "100-year" events in the last three years alone. Climate projections back up what the pattern already shows: the city has said that by 2050, maximum daily rainfall is expected to climb from 66mm to 166mm. What's called a "100-year storm" today is expected to happen every 30 to 60 years by the second half of this century — not once a century. None of this is offered to pile onto what you're already dealing with. It's offered because it changes the question from "why did this happen to me" to "what do I do so it doesn't happen again" — and that second question has an answer.

You have more control over this than it feels like right now

Here's what we want you to walk away with: basement flooding from sewer backup is one of the few home disasters that has a proven, physical, engineering-based solution. This isn't about luck, and it isn't about hoping the next storm misses you. A properly installed backwater valve creates a one-way barrier between your home's plumbing and the municipal sewer system. When the sewer backs up, the valve closes. Water that would have come up through your floor drain simply can't get in. It's not a gadget, it's not a maintenance subscription, it's a physical device installed correctly, once, by someone who knows what they're doing.

That's the work we do, every day, across the GTA. We're not asking you to trust a sales pitch. We're asking you to let us look at your specific home — your drain layout, your grading, your sump situation if you have one — and tell you plainly what's going on and what it would take to protect it. That's it. We assess, no guess. No inflated scare quote, no "you need everything right now" upsell. Just an honest look and a straight answer.

If you're not ready to book anything yet, start here

We know not everyone is in a position to schedule a home assessment this week — especially if you're still dealing with cleanup, insurance calls, or contractors for the damage itself. That's completely fair. If that's you right now, we put together a free resource that walks through the five warning signs that a basement is at elevated risk of flooding, in plain language, no jargon. It's the same checklist we use ourselves before we ever quote a job. You can grab it, read it in ten minutes, and use it to get a realistic sense of where your own home stands — no commitment, no cost, no pressure.

We've also been writing about exactly this — how Toronto's drain infrastructure works, what backwater valves do, how they compare to sump pumps, and what the real cost ranges look like for flood prevention work in this city — on our blog. It's there so you can read at your own pace, on your own time, and decide that's informed rather than rushed.

If your basement flooded this week specifically

If you're one of the homeowners dealing with actual water damage from Wednesday's storm right now, a few things matter in the short term, separate from anything we can help with long-term:

Document everything with photos and video before you start cleanup — your insurance adjuster will need it.

Get standing water out and start drying the space as soon as it's safe to do so; mould risk climbs fast in the first 24 to 48 hours.

If your basement flooded and you don't yet know why, that's exactly the kind of question an assessment answers. Sometimes it's a sewer backup. Sometimes it's foundation seepage. Sometimes it's both. The fix is different depending on the cause and guessing wrong means spending money on the wrong solution.

We're not going to pretend we can undo the damage that's already been done. What we can do is make sure this is the last time it happens.

Why now, and why this matters more than it might feel like it does

It's tempting, once the water's out and the carpet's replaced, to file this under "bad luck" and move on. We understand the instinct — nobody wants to keep reliving a stressful week. But here's the thing worth sitting with for a second: the conditions that caused Wednesday's flooding didn't go away when the rain stopped. The same aging stormwater infrastructure is still there. The same homes without backwater protection are still exposed. The next significant storm, whether it's next month or next year — will find the same gaps it found this week, in the same homes that didn't have them addressed.

That's not fear-mongering. That's just how infrastructure and plumbing work. A basement that flooded once because of a specific, identifiable, fixable gap will flood again from that same gap unless something changes. The good news is that "something changes" here is usually a single, well-executed installation — not a renovation, not a major disruption to your home, and for most properties, done in a day.

What booking an assessment looks like

If you decide you want a professional set of eyes on your home, here's exactly what happens — no surprises. We come out, we look at your drain layout, your grading, your existing plumbing, and where water is getting in or could get in. We tell you honestly what we find, including if the answer is "you're actually in decent shape" — that happens, and we'll say so. If there's real risk, we'll walk you through what a backwater valve installation involves, what it costs, and what the realistic timeline looks like. You decide from there. No pressure, no countdown timer, no "today only" pricing games. Just a real assessment from people who've done this work across Toronto, Scarborough, North York, Etobicoke, and East York for years.

The bottom line

You went through something hard this week, and if your home is one of the ones still drying out, we're genuinely sorry. What we don't want is for that experience to just become a bad memory you push down until the next storm brings it back up, literally. Whether you're ready to book an assessment today, want to start with the free eBook, or just want to read through what we've written about how this all works — every one of those is a real step toward not having this happen to you again.

Ready to find out where your home stands? Book your assessment with Wane Drain today — serving Toronto, Scarborough, North York, Etobicoke, and East York. We assess, no guess.

Not ready yet? Download “Basement Flood Prevention Guide” and get a clear, no-pressure picture of where you stand — link in bio, or on wanedrain.com.

Either way, don't wait for the next storm to ask the question. Ask it now, while it's calm.

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Sources

Toronto Life, "The Age of the Flood" — torontolife.com/city/the-age-of-the-flood

CP24/CTV News, "Here's a list of some of the worst floods to hit Toronto area in recent years," Sept. 3, 2026

CP24/CTV News, "What experts say caused the destructive storm that hit Toronto," Sept. 3, 2026

Canada's National Observer, "Toronto recovering from 100-year storm," Sept. 3, 2026

Global News, "Toronto begins recovery after '100-year storm'," Sept. 3, 2026