Why Your Backyard Floods (and How to Stop It for Good)
Backyard flooding has become a growing problem for many Toronto homeowners. As a landscaper with over 40 years of experience, I’ve seen this issue increase since the City of Toronto required the disconnection of downspouts from storm sewers. What used to be managed underground is now pushed into backyards, creating headaches for property owners—especially in areas with slow-draining clay soils or high water tables.
This article explains how to recognize if you truly have a flooding problem, what causes it, and what solutions are available.
Why Backyard Flooding Is More Common Today
Downspout disconnection: In the past, roof water drained directly into underground storm sewers. To reduce basement flooding during heavy rain events, which have become a common occurrence due to the increased density of housing that the City has experienced, the city requires that downspouts be disconnected. Now, all that roof water often ends up in your backyard.
Sump pump discharge: Older homes used to send weeping tile water into city sewers. Today, sump pumps push it out above grade—often into the backyard.
Soil conditions: Heavy clay soils common in Toronto absorb water very slowly. Add extra roof and foundation water to that, and you have standing water problems.
Do You Actually Have a Problem?
Not every puddle means you have a flooding issue.
No real problem: If water pools briefly in early spring after snowmelt but drains within a few days to a week, you likely don’t need to take action. The ground is probably still frozen and is definitely saturated with water from the spring thaw.
Problem worth solving: In summer, if water lingers for more than 24 hours after a heavy rain—or worse, you see it seeping into your basement—you need a solution.
Common Causes of Backyard Flooding
Poor grading – Your yard may slope toward the house or toward a low spot.
Compacted or clay soil – Prevents water from soaking in at a reasonable rate.
High water table or underground streams – Water has nowhere to go once it hits the subsurface.
Improper downspout/sump pump discharge – Too much water is being directed into one spot.
Solutions That Work
1. Regrading
If grading is the issue, the fix may be as simple as reshaping the yard to slope water away from the house and out toward safe drainage areas or spreading it over a larger area.
2. Soak-Away Pit (French Drain)
For persistent ponding, a soak-away pit or French drain may be required. Traditionally, these were built by digging a pit and filling it with ¾" clear gravel. Today, systems like Aquablox provide much greater storage volume because they are hollow and designed to capture more water with less excavation.
3. Redirecting Water
Sometimes the best solution is prevention:
Route downspouts to the front yard or into rain gardens.
Move sump pump discharge away from the backyard.
Spread water out instead of concentrating it in one spot.
4. When Not to Install a French Drain
If you have:
Heavy clay soil with poor percolation, or
A high water table / underground stream
…then even the best French drain system will not solve the problem. In these cases, minimizing water directed to the backyard is the only effective option.
Underground Soak-Away-Pit using Aquablox
Soak-Away Pit Installation
How to Test Your Soil’s Percolation Rate
A simple at-home test can help you gauge how well your soil drains:
Dig a hole about 12 inches deep and 6 inches wide.
Fill it with water and let it drain completely (this saturates the soil).
Refill the hole with water.
Measure how long it takes for the water level to drop one inch:
Less than 1 hour per inch – Excellent drainage.
1–4 hours per inch – Acceptable drainage.
More than 4 hours per inch – Poor drainage; French drains may not work well here.
For serious cases, a soil engineer should perform professional percolation and water table testing, usually at depths of 5 feet or more.
Legal Considerations
You cannot legally regrade your property so that water drains into your neighbour’s yard. Doing so can lead to disputes, repair costs, or even legal liability if water enters their basement.
When to Call in a Professional
Backyard flooding solutions can range from simple grading adjustments to engineered drainage systems. In many cases, hiring a soil engineer before spending thousands on drainage work is the smartest move—you’ll know if the soil can actually absorb water before you invest in French drains or soak-away pits.
Final Thoughts
Backyard flooding in Toronto is often the unintended consequence of changes in city stormwater management. While every property is different, the key is identifying whether you truly have a problem and then choosing the right solution based on the cause.
At Green Apple, we’ve helped homeowners across Toronto solve backyard flooding problems for decades. Whether it’s regrading, installing a soak-away pit, or redesigning how water leaves your property, we bring the experience to do it right the first time.
Ready to transform your outdoor space? Let us craft a modern, low-maintenance landscape designed to fit your lifestyle and elevate your home. Schedule a consultation today!
