Sewer lines are owned by you and the City.

  • The part that the City owns runs from the sewermain on the street to the property line.
  • The part that you own runs from the property line into the home.
  • Watch the City’s video on sewer lines to learn more about your plumbing system.

How to manage a blocked or backed-up drain can depend on where the issue is located. Get tips below.

Please report this to your landlord or superintendent.

This indicates a private plumbing issue. You may wish to contact a plumber.

When a resident experiences a blocked sewer service line and/or basement flooding, they should report the incident to 311. Reporting a call to 311 is important for several reasons:

  • Investigation: The City will dispatch staff to investigate and take steps to diagnose whether the reported blocked sewer service line and/or basement flooding was the result of an issue with the City’s infrastructure requiring the City to take steps to address it.
  • Sewer service line blockages: Multiple properties on the same street may have experienced basement flooding, which may be an indication that the sanitary sewer under the street has a blockage that needs to be cleared.
  • Inspection record: The City creates a record documenting calls to 311 reporting a blocked sewer service line and/or basement flood, along with the results of the investigation staff have completed. The results of the investigation and the inspection record plays an important role in the City’s third-party claims investigation process.
  • Infrastructure upgrades: The City refers to the information compiled from the number of calls received in an area that may help identify the performance of City infrastructure and/or if an area has a history of flooding. This information will help determine if any future infrastructure upgrades are required in the area.
  • Improves customer service: Reporting a blocked sewer service line and/or basement flooding can assist the City in planning and deploying field staff efficiently.

You can submit a service request online or call 311 to have Toronto Water investigate.

Your request will be investigated by Toronto Water staff within four hours*.  Please note that someone must be home in order for staff to access the property.

*During periods of heavy rain, which can result in high call volumes, it may take longer for staff to visit your home. Please contact 311 for the most up-to-date information.

Investigation Process

Step 1: Investigating the City sanitary sewer

Toronto Water staff will first investigate the sewers near your home to ensure they are draining properly. If they are not, staff will initiate an emergency work order to complete repairs and will notify you of the repair schedule.

Step 2: Investigating the sewer service line and the importance of cleanouts

If the sewers are draining properly, Toronto Water staff will inspect the sewer drain connected to your home. To investigate a blocked sewer service line, the water service technician will need access through a cleanout. Access to a working and accessible cleanout is essential to assist in troubleshooting basement flooding and/or a sewer service line problem. Cleanouts can normally be found on City property, on private property (inside or outside the home) or there is no cleanout. On private property, cleanouts are located in the basement or outside the home. If a proper cleanout and/or access to the sewer service line is not available, the water service technician will advise the property owner to install a proper cleanout before any investigation work can be performed. This may require the property owner to hire a licensed plumber.

An opening on private property that provides access to a sewer pipe

Depending on the location of the cleanout, the water service technician will first investigate the City-side portion of the sewer service line using closed-circuit TV (CCTV) to determine if there is a blockage. If the City-side is clear, then the problem would be determined to be on the private side of the sewer service line, the property owner is responsible for conducting repairs and will be advised to call a licensed plumber.

If the blockage is found on the City-side but the water service technician is not successful in removing the blockage, the water service technician is then required to obtain a Natural Gas Sewer Safety Inspection clearance before any other work can begin. In some instances, this natural gas inspection, which is not done by the City, could take a day. Once this clearance is received, the water service technician will attempt to remove the City-side blockage by use of an electric snake and/or plunging the sewer service line.

If the obstruction found on the City’s portion of the sewer service line cannot be unblocked by an electric snake and/or plunging, the water service technician may create a work order for a specialized crew to take appropriate action (for example, excavation).

When a cleanout is on the inside of the property, and it is safe to do so, the water service technician may be able to plunge and/or CCTV the cleanout. If it is not safe to do so, the property owner will be asked to hire a licensed plumber to investigate the private side.

Depending on the extent of the work required, which may include excavation, repairing a City-side blockage can take several hours or up to two days. Staff will discuss the process and repair timelines with the homeowner.

Investigations could be significantly delayed due to storm events that impact the City’s customer service response levels.

To learn more on sewer cleanouts, see below:


Blockages are clogs in the pipe and are typically caused by items that are incorrectly flushed down the drain. The most common offenders are:

  • Fat, oil and cooking grease, which cool, harden and stick to the inside of pipes.
  • Wipes of any kind – even those that say “flushable” do not break down.
  • Condoms, sanitary supplies, dental floss and other personal hygiene products.

Get more details on what not to flush or pour down your drains and how to dispose of these items.

Tree roots

Roots from nearby trees can grow into the sewer pipe and cause holes and blockages.

Broken or cracked sewer pipes

Sewer pipes can break down and crack over time, especially those built in older homes that may contain cast iron or clay pipes.

Heavy rain

During periods of heavy rain, the sewers can sometimes become full, which can cause water to enter the home. Learn more about the different kinds of sewers and view videos on how to protect yourself against basement flooding.