Flood Prevention

Kirkland’s territory is equipped with SEPARATE sewer systems, which cover approximately 117 km. 

This type of system comprises two separate pipes, one for sanitary water and the other for run-off water generated by rain and snowmelt.

The City carries out regular maintenance of the public sewer network throughout the year, including inspection and cleaning of the 3,400 street catch basins and retention basins the network encompasses.

Wastewater Management

Sanitary Sewer System

Wastewater collected by the sanitary sewer system comes from the household’s sanitary installations: toilets, bath, shower, washbasin, kitchen sink, washer, dishwasher and floor drains.

This water is sent to a wastewater treatment plant for treatment before being discharged into the surrounding waterways.

Storm Sewer System

The water collected by the storm sewer system comes from the foundation drains of the house (French drains) and from runoff generated by rain and snowmelt. 

This water is discharged directly into the the natural environment, without treatment.

The backflow water valve prevents wastewater collected by the municipal sewer system from flowing back into the home’s basement through plumbing fixtures or floor drains during heavy rains.

Types of Backflow Valves

There are two main types of backflow water valves:

1.  « Normally CLOSED » Backflow Valve

In normal operating mode, the valve door remains closed and opens only for normal sanitary and rainwater drainage from the house. 

In the event of backflow, this door blocks water flowing in the opposite direction.

Installations with this type of backflow valve must be equipped with a cleanout inside the building for providing regular maintenance.  

2.  « Normally OPEN » Backflow Valve

In normal operating mode, the valve door remains open, and closes in the event of backflow to block water flowing in the opposite direction.

A « normally open » backflow valve can only be installed on the sanitary sewer if it serves a single dwelling.

Installations with this type of backflow valve must be equipped with a cleanout inside the building for providing regular maintenance.

All backflow water valves and cleanouts must be installed in such a way as to be accessible for regular maintenance and emergency intervention when the situation so requires.

An access door or removable panel must be provided when inside a wall or under a false floor.

Precautionary Measures

For optimum backflow protection, it is essential that each backflow valve be properly installed, maintained in good working order, and accessible at all times.

To be sure, it is advisable to call in a professional plumber who is a member of the Corporation des maîtres mécaniciens en tuyauterie du Québec (CMMTQ).

When rain falls on the ground, it is evacuated in different ways depending on the type of surface:

• Infiltration into the ground
• Standing water on the ground
• Runoff into the sewer system or to the lowest point.

Each type of surface absorbs water in varying amounts.  For example, for the same amount of rainfall, the grass portion of a property (permeable surface) absorbs much more water than the asphalt portion (impermeable surface).

During heavy rainfall, this solution is particularly effective at capturing rainwater, draining an additional flow of rainwater, and reducing the load on the French drain. What’s more, this solution helps prevent seepage around the foundation, providing additional protection against flooding in the home’s basement.

Regular maintenance of plumbing fixtures

Providing regular maintenance of your home’s plumbing systems (pipes, backflow valves, cleanouts, gutter system, sanitary and storm sewer connections) is an effective way to prevent future problems. 

Seek out the services of a professional plumber who is a member of the Corporation des maîtres mécaniciens en tuyauterie du Québec (CMMTQ) to check the key elements and plan the necessary work.

Things not to do when it is raining heavily...

In the event of heavy rainfall, a closed backflow water valve may block wastewater draining from the building to the sewer.

To prevent the sewer backups that this situation can cause, it is advisable to avoid the following when you are at home and it is raining heavily:

• Flushing the toilet
• Taking a shower or emptying a bathtub
• Using the washing machine or the dishwasher
• Any other use of water that could activate your home’s sewer system

A foundation drain or French drain is a pipe installed underground around the foundation of a building, designed to capture water seeping into the ground and carry it away from the house.

If this drain’s piping system is unable to evacuate the groundwater properly, the water will pool in the soil around the house’s foundations and can seep through cracks into the foundation walls, creating a risk of seepage flooding.

It is important to regularly maintain your drainage system to ensure your home’s foundation is watertight and free of cracks. 

To this end, it may be useful to call on the services of a professional in the field.

Gutters are designed to protect your home from rainwater by diverting it away from the house and its foundations.

Water collected by a gutter system must be directed at least 1.5 m from the foundation of the house towards the vegetation on the property (lawn, trees, shrubs, flowerbeds).

No gutter may be connected to a storm drain, sanitary sewer, or foundation drain (French drain). 

In fact, such connections are prohibited because they contribute to overloading the municipal sewer system by increasing the amount of runoff water that flows into it, especially during heavy rainfall.