Apply for a wastewater discharge permit

Is your establishment likely to discharge wastewater into a sewer system or waterway on the island of Montréal? You must comply with certain requirements and hold a permit. Did an accidental spill occur? You must let us know quickly.

On this page:

Provincial permits

In the event of a direct discharge into the St. Lawrence River, the Rivière des Prairies, Lac Saint Louis or Lac des Deux Montagnes, you must apply to the Ministère de l’Environnement, de la Lutte contre les Changements climatiques, de la Faune et des Parcs (MELCCFP), which will set specific limits on a case-by-case basis.

Permit for an industrial establishment

In some cases, approval is required instead of a permit. If you’re not sure, write to us to find out the requirements for your situation.

The permit is issued within 75 working days if your application is in order and compliant. You must receive your permit before discharging any wastewater. 

Here are some examples of elements to document in your application: 

  • How processes that generate wastewater are monitored
  • Source control devices (reduction of flow rate and which contaminants are discharged)
  • Accidental spill control measures
  • How processing systems are kept in operation
  • How records are kept of the operation and maintenance of processing systems
  • Your periodic monitoring and analysis program

Apply by e-mail

Please complete and send us this form (in French). Engineering documents submitted with the application must be authenticated by an engineer.

[email protected]

Permit for a dental office

You must have an amalgam separator to limit mercury releases to the sewer and avoid contaminating the environment.

Apply by e-mail

Please complete and send us this form (in French).

[email protected]

Permit for sludge discharge from septic tanks or chemical toilets

You must apply for an annual permit. You will then have to pay a fee for each spill. Costs are calculated according to the volume of the tank and the dryness of the sludge.

Apply by e-mail

Please complete and send us this form (in French), as well as a copy of the registration certificate for each truck or semi-trailer.

[email protected]

Accidental spill reporting

Don’t have a permit yet? Does your permit include restrictions with which you did not comply? Has your permit expired? 

You must report any accidental spills immediately. Call us right away at 514-280-4330. 

Once you’ve called us, follow these steps: 

  • Complete the form (in French) and send it to us by e-mail.
  • Within 15 days of the spill, send us an additional declaration, specifying the causes of the event and the corrective measures you’ve implemented. Use one of these documents depending on your situation: various industries or surface treatment industries. Depending on your situation, use the “General Industries” document or the “Surface Treatment Industries” document.

By-laws 

Overview of applicable by-laws. 

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Last updated December 16, 2025