Downspouts, Sewers and Toronto Rules

In a nutshell

Toronto has required most properties to disconnect downspouts from the sewer system, with exemptions where disconnection is not feasible. Disconnected downspouts send rain onto lawns and gardens instead of into overloaded pipes.

The reasoning is simple arithmetic. A modest Toronto roof can shed thousands of litres in a heavy summer storm. When hundreds of houses on a street pipe all that water into a sewer sized for household waste, the system fills and the extra has to go somewhere, often into the lowest basements on the line. Disconnecting spreads that water across lawns and gardens, where much of it soaks in. Rain barrels at the base of a disconnected downspout capture some for watering, though they need draining before winter.

Be careful where the extension points. Send the runoff a good stride or two past the foundation, across soil that slopes off, and stay off the neighbour's lot, any path that could freeze, and every window well. Splash pads under the outlet keep the soil from eroding.

Working through it

1. Find the connection

Where the downspout enters a pipe in the ground.

2. Cut the downspout

Above the standpipe.

3. Cap the standpipe

A tight cap stops sewer gas and water.

4. Add an elbow and extension

Direct water away.

5. Check the grade

Ground should slope away.

Clues worth noticing

• Pooling by the foundation.
• Downspouts still entering the ground.
• Leaks after rain.
• Erosion.

Signals that it needs a licensed plumber

For broader flood protection, see basement flooding.