Ville de Gatineau
Reversed connections
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Reversed connections
Reversed connections

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What exactly is a reversed connection?

A reversed connection is an improperly connected or defective connection in equipment that enables wastewater to run elsewhere than into a sanitary or combined sewer system. The water might be flowing:

  • into a storm sewer;
  • onto the ground;
  • into a ditch; or
  • into a waterway.

Reversed connections may be a result of:

  • plumbing errors;
  • improper connections; or
  • defective equipment.

Reversed connections can constitute a source of pollution for beaches, lakes, waterways and wetlands. Given that water quality is paramount to maintaining biodiversity and our quality of life, it is essential that reversed connections be eliminated.

A reversed connection is NOT…

An unlawful connection of a storm sewer to the sanitary sewer system.

There is an obligation to act:

  • Undertaking 37 of the Québec Water Policy: “To eliminate (…) wastewater discharges during periods of dry weather”;
  • Agreements signed between Ville de Gatineau and the ministère des Affaires municipales et de l'Habitation (MAMH) under government assistance programs (Quebec Municipalities Infrastructure Program [PIQM] and the Building Canada Fund - Quebec [BCFQ]).

Thus, every municipality that has a storm sewer system and that has signed an agreement with MAMH under one of these government assistance programs is required to implement a program to eliminate reversed connections. According to MAMH, close to 250 municipalities in Quebec have such agreements.

Gatineau developed an action plan to eliminate reversed connections in its municipal sanitary sewer systems. That action plan involves identifying and correcting reversed connections throughout its territory.

Gatineau is currently identifying reversed connections for an overview of the situation within its territory.


  • Inspection and sampling of vents: This first phase, carried out in 2017-2018, aimed to assess the likelihood of the existence of reversed connections.
  • Inspection of manhole covers: In order to identify which sections of the sewer system have reversed connections, manhole covers were lifted in dry weather to check for water runoff. Storm sewers were checked from upstream to downstream where there was no runoff.
  • Confirmation tests
    • Smoke testing
      This quick and relatively inexpensive technique helps isolate possible connection problems in the sewers. Smoke testing involves using a fan to inject non-toxic smoke into the sewer system to pinpoint problem areas in buildings. Buildings where smoke is found to escape are marked for inspection.

      Photo: EnviroServices

      Photo: EnviroServices
    • Tracer testing
      This technique is used to confirm possible reversed connections. The operation involves pouring a tracer into a sink or toilet in a building and checking to see where it ends up in the storm and sanitary sewer systems. Tracers may be non-toxic and non-staining dyes or floating balls like ping-pong balls.

      Click here to fill out the appointment request form

Référence: Ministère des Affaires municipales et de l'Habitation

Corrective measures

Gatineau is still at the stage of identifying problem areas, so no corrective measures are required on the part of property owners, nor will any notices of violation be issued. Gatineau is reviewing its by-law on sewer and water supply system connections. The new by-law will, among other things, establish how the costs of corrective measures are to be allocated between the municipality and the property owner based on a number of factors.

About Gatineau

Recognized for its quality of life, Gatineau is a city of 292,000 inhabitants. It is located on the north shore of the Ottawa River, and extends east and west of the Gatineau River.

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