Plumber in Laval, day and night

City of Laval by-law L-11870 requires a valve on every drain connection located below the crown of the street, upstream of the main building drain. Three details change how the work is done in Laval:

• only normally closed valves are allowed, and gate valves are prohibited;
• no valve of any kind may be installed on the main building drain;
• a floor drain with a built-in device does not replace the valve on the connection.

The fact sheet the City published in 2026 also lists the built-in Gendron valve, the built-in backflow device and a normally open valve on the main building drain as non-compliant. The by-law requires cleaning the valves at least once a year, and the City recommends doing it in spring and fall. Without the required devices, the City says it is not liable for damage caused by a backup.

Before installing or replacing a backwater valve, the plumber checks how your drains are connected and which fixtures sit below the crown of the street. That determines how many valves you need and where they go.

The City of Laval asks residents to call an RBQ-licensed plumber first. If the plumber confirms the City needs to step in, call 311 and keep the plumber’s invoice: the City asks for it as proof of the visit.

Maintaining the connection on your own land is at your cost. The boundary with the City’s part is the centre of the curb stop on the water line. More than 7,000 km of water and sewer pipes run under Laval’s streets.

The company holds an RBQ licence and is a member of the CMMTQ. During a sewer backup, the plumber clears the line, looks for the cause and tells you whether it is on your side or the City’s.

In Laval, only a City employee may open or close the water service valve on your property. For work that requires shutting off the water there, you have to go through 311. The by-law sets a fine of $500 to $1,000 for a first offence by an individual.

By-law L-12778 also prohibits letting municipal water run to keep a pipe from freezing, unless the City directs it. When a pipe has frozen, the plumber thaws it and checks that it has not split before turning the water back on.

The City says a house built before 1967 may have a lead service line, and suggests four checks: where the pipe runs, its grey colour, the sound it makes and a magnet that does not stick to it. According to its municipal plan, updated in July 2022, about 50 lead service lines remained to be replaced and 33 had been replaced since 2007, all in buildings built before 1955.

When the City’s part is lead and yours is copper, Laval commits to replacing its part with copper within 15 days. If only the private part is lead, the owner receives a letter recommending its replacement. Replacing your lead water service line covers the pipe from the house to the curb stop.

Laval is an island bordered by the Rivière des Prairies and the Rivière des Mille Îles. According to the City, the spring flood runs roughly from March 15 to May 15. On August 9 and 10, 2024, the rain left by storm Debby dropped between 125 and 200 mm of water on the territory.

These events put connections and valves to the test. Before spring and before summer, check that your valve moves freely and that nothing is blocking your floor drains. If water drains slowly, drain cleaning before the rainy season keeps it from backing up at the wrong time.

We work anywhere on the island, day and night, for emergencies and planned work alike. The price is confirmed on the phone before the plumber heads out, and the arrival time is confirmed for your address when you call.