How is a Calgary sump discharge routed?

In Calgary, sump pump discharge must be routed to daylight on your property — never into the sanitary sewer, weeping tile system, or storm sewer. The City of Calgary's sewer bylaw prohibits connecting sump pumps to the sanitary system, and for good reason: during heavy rain and snowmelt events, sump water flooding the sanitary system contributes to basement backups across the city.

The standard approach is to run the discharge pipe through the rim joist (the band of framing just above your foundation wall) to the exterior, then direct it across your yard so water flows away from the foundation. The pipe should terminate at least 1.5 to 2 metres (5–6 feet) from the foundation wall, and the discharge point must be on your own property — you can't direct it onto a neighbour's yard or into the back alley in a way that causes drainage problems. The outlet should be positioned so water flows toward the street, a drainage swale, or a low point in the yard that naturally carries water away.

Inside the home, the discharge line is typically 1.5" or 2" ABS or PVC pipe running from the sump pit up through the basement ceiling or along the wall to the rim joist penetration. A check valve is essential — installed close to the pump — to prevent water from draining back into the pit when the pump shuts off, which would cause the pump to short-cycle and wear out prematurely. The pipe should slope continuously upward (no dips where water can sit and freeze) until it exits the building.

Calgary's climate creates a real challenge with exterior discharge. During a January cold snap at -30°C, the discharge line and exterior outlet can freeze solid — right when you might need the pump most during a mid-winter chinook melt. Common solutions include insulating the exterior portion of the pipe, using a freeze-proof discharge outlet (a flap-style or weighted cover that closes when not flowing), and making sure the pipe has enough slope to drain completely after each pump cycle so standing water doesn't freeze in the line. Some homeowners run the discharge into a dry well or infiltration pit in the yard, which works well in sandy or gravelly soils but is problematic in Calgary's clay-heavy ground, where water simply won't absorb fast enough.

Permits and inspections — a sump pump installation or replacement typically requires a plumbing permit from the City of Calgary. If you're adding a new discharge penetration through the foundation or rim joist, that work should be inspected. Call 311 or visit calgaryplanningpermit.ca to confirm what's required for your specific scope.

For the actual installation or if you're troubleshooting a freezing discharge line, a licensed plumber familiar with Calgary's conditions is your best resource. Browse local plumbing contractors in the Calgary Construction Network directory to find someone who knows the city's clay soils and freeze-thaw realities firsthand.