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Manhole cover on a Saint John street

Stormwater and Drainage

The water from big rainstorms or spring runoff has to go somewhere. In urban and developed areas, hard surfaces like roads, roofs, driveways, and parking lots prevent water from seeping naturally into the ground. Saint John's urban stormwater management service maintains a drainage system that carries rain and other water away from infrastructure and property—which greatly decreases the risk of flooding. This system includes 325 km of storm sewers, 2,172 combined (storm and sanitary) sewers, 9,417 catch basins, 4,934 storm manholes, and 2,172 combined manholes.

Help protect our stormwater system

Stormwater flows into our creeks, streams, rivers, and the ocean through outfalls—the concrete drains you see along the river or the Bay. If the stormwater is polluted, it can affect the health of our water systems, the land surrounding them, and the health of the wildlife and fish that rely on them.

Help protect our rivers with these tips:

  • Never pour anything down the storm drain
  • Point downspouts toward lawns and gardens
  • Use a rain barrel with your downspouts
  • Limit the use of fertilizers and pesticides
  • Sweep up debris from your garage and driveway instead of washing it away
  • Wash your vehicle at a car wash

Help protect your own property

A flooded basement is more than just a nuisance. Restoration of a finished basement can cost thousands of dollars, and may cause your insurance premiums to rise. A municipal storm sewer and drainage system alone can’t guarantee basement flood protection. Here’s what you can do to help reduce the risk. 

Effective downspout drainage

Downspouts should be disconnected from the weeping tile and extend at least 1.8 metres (six feet) from your basement wall to drain away from the house toward a street or drainage swale. This ensures roof water doesn’t enter onto the weeping tile around your foundation.

Proper lot grading

Land should slope outward from the foundation of the house for a minimum of 1.8 metres (six feet). If the lot slopes toward the house, surface water will enter the weeping tile and overload the drainage system. Use impervious materials such as clay or a plastic drainage mat near the surface to limit the amount of surface water that finds its way to the weeping tile.


A swale is a wide shallow channel with gently sloping sides. Provide swales along the back and/or side property boundaries to limit flows towards your house. The swales should be as large as possible to slow runoff.

Sump pumps

If water continues to enter your basement, a sump pump in a sump pit can be used to periodically remove it. A sump pump arrangement includes a pump, and a sump basin—typically a 60cm x 60cm x 30cm deep (2ft x 2ft x 1ft deep) pit. The sump pump should discharge the water onto your property, well away, 1.8 meters (6ft) from the foundation walls.

Backflow preventers

A backwater valve reduces the possibility of the storm sewer from backing up into your building drain. A backwater valve is recommended on all sanitary sewer laterals to reduce the risk of basement flooding from the sanitary sewer.

Rain gardens

Rain gardens are planted depressions that are designed to absorb rainwater runoff from impervious areas like roofs, driveways, walkways, and compacted lawn areas. This reduces rain runoff by allowing stormwater to soak into the ground.