Most drainage advice online was written for places that do not freeze. In Southern Ontario the ground swells, lifts and drops several times a winter, and clay soil holds water against everything you build. A solution that works fine in Virginia can be a waste of money in Halton.
Before you spend anything, work out which of three problems you have, because they need different fixes and the wrong one is expensive.
First: where is the water coming from?
- 1
Surface water
Rain running across the ground and collecting in a low spot, or sheeting toward the house. You can see it happen during a storm. The fix is almost always shaping the ground, not burying a pipe.
- 2
Subsurface water
Water moving through the soil, often from higher ground, showing up as an area that stays soggy days after rain with no obvious source. This is what a French drain is genuinely for.
- 3
Roof and hardscape water
Downspouts discharging at the foundation, or a large patio and driveway concentrating runoff into one place. The cheapest of the three to fix and the most commonly ignored.
Regrading — the fix people skip
Reshaping the ground so water runs away from the house and toward somewhere it can leave is the least glamorous option and very often the right one. There is no pipe, nothing to silt up and nothing to fail in frost, which in this climate is a substantial advantage.
It is also dramatically cheaper when done at the same time as other work. If you are replacing a lawn, the topsoil is already off, and correcting the grade at that moment costs a fraction of what it does as a standalone job later.
- Best for: surface water, low spots, ground sloping toward the foundation
- Nothing to maintain, nothing to freeze
- Needs somewhere lower for the water to go, same as any solution
- Often disruptive to lawn and planting while it is done
French drains — good for the right problem
A trench of clear stone with a perforated pipe in it, wrapped in filter fabric, sloped to somewhere lower. It intercepts water moving through soil and carries it away. Done properly it lasts decades.
Done improperly it does nothing at all, and the failures are consistent. The most common is no outlet — a stone trench with nowhere lower to discharge simply fills up and stops accepting water. The second is no filter fabric, which in clay soil means the voids between the stone silt up within a few years and the trench becomes functionally solid.
Roughly half the failed drains we dig up had no outlet at all. They were built as a trench and hoped to work as a system.
The third failure is inadequate fall. Water needs continuous slope along the pipe, checked with a level rather than judged by eye. A dip in the middle holds standing water, silts faster and freezes.
- Best for: persistently soggy areas, water arriving from higher ground, damp foundation walls
- Requires a viable outlet — this is not optional
- Needs clear washed stone, not crusher run or screenings
- Filter fabric is what determines whether it lasts five years or thirty
Dry wells — when there is nowhere to drain to
A buried chamber or stone pit that gives water somewhere to collect and soak away slowly. Useful on flat lots where there is genuinely no lower point to discharge to, which is a real situation in parts of both Oakville and Burlington.
The catch is soil. A dry well only works if water can actually percolate out of it, and heavy clay percolates slowly. On tight clay a dry well can become a buried bathtub that fills in spring and stays full. It needs to be sized for your soil, and sometimes the honest answer is that the site will not support one.
Swales — the visible option
A shallow, broad, gently sloping channel that moves surface water across a property. Planted, it reads as a natural dip in the lawn rather than a piece of infrastructure, and it handles large volumes without any buried components to fail.
Swales need space and they need to go somewhere. On a narrow urban lot there often is not room, and a swale that dead-ends is just a longer puddle.
Downspouts — always check this first
A downspout discharging at the base of a wall puts an enormous volume of water exactly where you least want it. A significant share of the wet-basement calls we get are solved by extending downspouts well away from the house and correcting the grade in that one area.
It is the cheapest fix in landscaping and it is worth ruling out before anyone quotes you for excavation. If a contractor arrives, ignores your downspouts and proposes a large drainage installation, get another opinion.
What freeze-thaw actually does
Water expands as it freezes, so anything holding water in winter is being pushed apart repeatedly. This is why material choice matters more here than in milder climates.
- Limestone screenings hold water and heave. Clear stone drains and does not.
- Pipe laid flat holds water, freezes solid and stops working exactly when spring melt arrives.
- Shallow installations sit in the frost zone and get lifted every year.
- Backfilling a trench with the clay that came out of it defeats the whole installation.
So which one do you need?
- Water pools in one low spot after rain — regrade
- Ground slopes toward the house — regrade, and check the downspouts
- An area stays soggy for days with no visible source — French drain
- Water arrives from a neighbouring property uphill — interceptor French drain
- Wet basement wall on one side of the house — downspouts and grade first, then a perimeter drain if it persists
- Nowhere lower to send water on a flat lot — dry well, if the soil will take it
- Large volume crossing a big property — swale
Most real properties need two of these together, and the sequence matters: fix the cheap and obvious things first, then see what remains. Anyone who quotes a large installation without first establishing where the water comes from and where it can go is guessing with your money.