Water and Sewer Systems

The City of Vaudreuil-Dorion operates a filtration plant and several wells to provide drinking water to its citizens. It also manages wastewater treatment works in the sectors served by the municipal sewage system.

Drinking water

Drinking water is supplied by the filtration plant, which draws its raw water from the Ottawa River. The filtration plant also serves the neighbouring municipalities of Vaudreuil-sur-le-Lac and L’Île-Cadieux. Its capacity increased from 18,000 to 40,000 cubic metres of water per day after a second water intake was added and a plant upgrade and expansion project was carried out between 2012 and 2016.

The main process steps are as follows:

  • Raw water intake
  • Low-pressure pumping
  • Ozonation pre-treatment
  • Sedimentation
  • Filtration
  • Ozonation post-treatment and disinfection
  • Chlorination
  • Adjustment of pH
  • High-pressure pumping (distribution)

See the Vaudreuil-Dorion water course.

Dorion is supplied by two pumping stations with a total of seven wells. The groundwater undergoes the following processes: disinfection, softening (colour and corrosion inhibitor), distribution to consumers and storage in the water tower near Place Dumont.

In autumn 2022, the Bélair sector (435 homes) was transferred to the Blue distribution network (formerly Vaudreuil). Only the areas in red on the map are now served by the Red network (formerly Dorion).

Reseaux_bleu_rouge_2023.png (917 KB)


The Hudson-Acres and Ritchie segments are connected to the distribution network of the filtration plant since June 26, 2019 and are now part of the Blue (Vaudreuil) system. 

The Murphy sector gets its drinking water from the system in the municipality of Hudson, while the Haute-Rive Summerlea sector is supplied from Pointe-des-Cascades.

Quality of drinking water

The Ministère de l'Environnement et de la Lutte contre les changements climatiques requires that the agency responsible for a drinking water distribution system produce a report on the quality of the water delivered for human consumption during the period from January 1st to December 31st of the preceding year. This report must include the minimum number of samples required under the Regulation respecting the quality of drinking water (RQEP), the number of samples taken for each parameter, as well as the number of samples tested by an accredited laboratory during this period.

2022 Water quality reports


The journey of water: from the lake to the tap and back to the lake

by Christian Gendron, Director of the Water Department of the City of Vaudreuil-Dorion

Boil Water advisory

Boil Water advisories are aimed at protecting public health. They may be issued as a precaution, for example if there is a risk of contamination following repairs to a water main, or if tests on raw water (before treatment) show levels exceeding the guidelines. The municipality is then required by law to issue an advisory, even if the test results were for untreated water.

When water is boiled for a minute or more, all potentially harmful micro-organisms are killed.

If water is not fit for drinking even after boiling, a Do Not Use advisory will be issued and the City will take special measures to ensure that the public is informed.

How does the City inform citizens of a Boil Water advisory?

If the advisory targets a small area, such as a few streets affected by a broken water main, the Public Works Department will hang a notice on the door of each home. If a large part of the city is affected, various means are used to inform the public:

  • An automated calling system can reach you by phone or text message. Please make sure you are signed up.
  • An urgent message will be permanently displayed on the City's website.
  • It will appear on the City's Facebook page and Twitter account.
  • It will appear on the electronic billboards at roads entering the city.
  • The media will also be informed.

What to do in the event of a Boil Water advisory

Until further notice, you must use bottled water or water that has boiled for at least one minute for the following:

  • Drinking water or using it to mix drinks
  • Preparing baby formula or baby food
  • Washing and preparing foods eaten raw (fruit and vegetables)
  • Preparing foods that do not require prolonged cooking (canned soup, desserts, etc.)
  • Making ice cubes
  • Brushing your teeth and rinsing your mouth   

You may use unboiled tap water for the following:

  • Washing dishes in hot water, but be sure to wipe them thoroughly dry
  • Washing clothes and taking a shower or bath
  • When bathing small children, make sure they do not swallow any bath water.   

Schools, businesses, shops and institutions

Inform your clientele that the water is unfit for consumption. Shut off all drinking fountains and post notices in places where water remains available.

Read the pamphlet produced by the Ministère de la Santé et des Services sociaux to find out more about what to do in the event of a Boil Water advisory.

Water main flushing

Each year—usually in April and May—the City flushes the water mains and inspects the fire hydrants. This work is done at night, between 10 p.m. and 6 a.m. To flush out sediment and mineral build-up, the valves are opened, allowing the flow of large quantities of water which are discharged through the fire hydrants. The flushing is done through predetermined routes that ensure optimum cleaning.

Because it is a large-scale operation, it can cause a slight drop in water pressure; it may also cause the water to be rust-coloured, which can lead to certain inconveniences such as stains on fabrics. Clothing and dishes should therefore be washed between 6 a.m. and 10 p.m. on weekdays or at any time on weekends. If your water looks rusty, turn on the cold water in your bathtub and let it run until it is clear.

Water lines

To request service, contact the Public Works Department at 450-455-3371, ext. 2550 or t.publics@ville.vaudreuil-dorion.qc.ca.

Opening and closing of water lines

The Public Works Department is responsible for opening and closing water lines for road work. Before you call a plumber, please allow a 48-hour or 72-hour wait period, since the City has to check the condition of the equipment.

  • If the water inlet is functional, once verified, the Public Works Department will contact you to schedule an appointment, depending on the availability of the parties involved, to open or close the water inlet.

  • If the water inlet is found to be non-functional, additional time will be required for repairs. It is not possible to specify these. Once the water inlet is repaired and functional, the Public Works Department will contact you to schedule an appointment, depending on the availability of the parties concerned, to open or close the water inlet.

  • Please note that there will be two closures per day, at 8 a.m. and 8:30 a.m., Monday to Thursday.

Location and relocation of water lines

Before undertaking any landscaping projects in front of your property or paving work in a driveway, it's important to locate the water inlet. To find out where the water inlet is on your property, or to have it adjusted, contact the Public Works Department, which will take care of the work. Levelling of the water line may be necessary following driveway repairs. Only city employees are authorized to handle municipal water lines.

  • You must allow a period of 10 days for this.
  • Relocation of the water line, depending on the work planned, can take up to 20 days.


The City of Vaudreuil-Dorion has its own wastewater treatment plant consisting of three units: liquid treatment, sludge processing and odour control. The plant has a capacity of 36,550 cubic metres per day and its main pumping station can handle 50,000 cubic metres per day.

Liquid treatment

  • Low-pressure pump
  • Pre-treatment (screening, grit removal)
  • Biological treatment [SBR (Sequencing Batch Reactor, commissioned in 1998), MBBR (Moving Bed Biofilm Reactor, commissioned in 2017)]
  • Sedimentation
  • Ultraviolet disinfection

Sludge processing

  • Sediment and activated organic sludge pumping
  • Sludge storage and mixing tank
  • Sludge dewatering (conditioning, rotary drum thickeners, centrifuges)
  • Sludge transportation and reclamation

Odour control

  • Foul air from the new facilities is sent to the BIOREM odour control system (ventilation of basins and rooms, air humidification, biofilter media, exhaust duct).
  • The air in certain rooms is treated by activated-charcoal filter units.

Septic systems

A septic system, which consists of a tank and septic field located on your property, treats wastewater and releases it into the groundwater. The water is cleaned through natural decomposition processes.

The septic field has a limited lifespan that depends on the quantity of wastewater treated, soil type, and frequency of tank maintenance and pumping. Proper maintenance will prolong the system's service life.

The discharge and treatment of wastewater from isolated homes is governed by a 1981 provincial regulation which each municipality is responsible for enforcing. Pollution by septic systems is of course strictly prohibited. Any system that is outdated must be replaced. If your property has a septic system, be sure to empty the tank every two years. Keep your receipt and send a copy to the City by email at infourbanisme@ville.vaudreuil-dorion.qc.ca as proof of maintenance.

If the grass over the septic field is very green or spongy, if there is an odour, if a grey or black liquid appears at the surface or if wastewater is not discharging well, it could mean your septic system is not working properly. A septic tank that has not had proper maintenance can cause serious problems: contamination of drinking water, sewage backups, impacts on your health and the environment, and decreased property value. The proper functioning of your septic system is your responsibility.

How to maximize the performance of your septic system

  • Use biodegradable products
  • Use phosphate-free soaps
  • Conserve water
  • Avoid compacting the soil
  • Avoid saturating the ground with water

For information on this topic, contact the Permits and Inspections Division.

RV Pumpout Station

* The station is open from early May to late October.

A pumpout station is accessible 24/7 on the site of the wastewater treatment plant located at 2565 Paul-Gérin-Lajoie. 

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Location of the pumpout station

Accidental spill report

Are you responsible for the accidental spill of a contaminant or a non-standard discharge into wastewater treatment works (sewer line, open ditch, etc.)? Is this spill likely to reach a wastewater facility? If so, you must immediately report it to the City of Vaudreuil-Dorion's Water Department by filling out the Accidental Spill Declaration form and sending it by e-mail, or by fax to 450-424-8570.

Prompt reporting allows for appropriate response measures to be put into place, health and environmental risks to be reduced, and contaminant recovery to be carried out in accordance with by-laws.

By-law No. 2008-47 regarding wastewater treatment for the Montreal Metropolitan Community (MMC)   

Article 14 – Accidental spills and corrective measures  

  • a) Any person who is responsible for the accidental spill of one or more of the contaminants identified in Section 6 or of wastewater which does not comply with the standards of this by-law and the spillage of which is likely to reach or sure to reach wastewater works and be detrimental to public health, public safety, the environment or the wastewater works, must immediately report the spill to the person responsible for enforcing this by-law so that measures may be taken to prevent such damage.
  • b) The Declaration shall include the location, date and time of the spill, duration of the spill, volume spilled, nature and characteristics of the contaminants spilled, name and telephone number of the person reporting the spill, and actions already taken or underway to mitigate or stop the spill (information requested on the form).
  • c) The Declaration must be followed within 15 days by an additional declaration establishing the causes of the spill and the measures taken to prevent its recurrence (information requested on the form).