Real-time overflow and bypass information

Share Real-time overflow and bypass information on Facebook Share Real-time overflow and bypass information on Twitter Share Real-time overflow and bypass information on Linkedin Email Real-time overflow and bypass information link


About the project:

The City of London has launched a new webpage online to share real-time and historical information about overflows and bypasses from the City’s wastewater facilities. By creating a publicly accessible internet resource that shows current overflow activity, Londoners are provided with a new tool to help them make decisions regarding activities in areas that could be affected.

The new real-time notification website can be viewed here

We are also collecting feedback about this webpage. Please share your comments with us

The City regularly posts information about overflow and bypass volumes and locations to the webpage london.ca/sewers. Information from this year and past years is available online.

Greenway Wastewater Treatment Facility in London, Ontario


Overflows and bypasses

A sewer system overflow occurs when sanitary sewers are overwhelmed by stormwater or other unwanted water during wet weather events. Overflows result in untreated wastewater being directly discharged to local waterways from the sewer system, at pumping stations and upstream of treatment plant inlets.

A wastewater treatment plant bypass occurs when the flow exceeds capacity of a treatment process within the treatment plant. During a bypass, partially treated wastewater and storm water may be discharged. The wastewater treatment plant fully treats as much sewage as possible prior to any bypass, and then provides partial treatment to everything else.

Overflows and bypasses are a last resort measure to prevent basement flooding and damage to treatment processes during severe weather.


About the project:

The City of London has launched a new webpage online to share real-time and historical information about overflows and bypasses from the City’s wastewater facilities. By creating a publicly accessible internet resource that shows current overflow activity, Londoners are provided with a new tool to help them make decisions regarding activities in areas that could be affected.

The new real-time notification website can be viewed here

We are also collecting feedback about this webpage. Please share your comments with us

The City regularly posts information about overflow and bypass volumes and locations to the webpage london.ca/sewers. Information from this year and past years is available online.

Greenway Wastewater Treatment Facility in London, Ontario


Overflows and bypasses

A sewer system overflow occurs when sanitary sewers are overwhelmed by stormwater or other unwanted water during wet weather events. Overflows result in untreated wastewater being directly discharged to local waterways from the sewer system, at pumping stations and upstream of treatment plant inlets.

A wastewater treatment plant bypass occurs when the flow exceeds capacity of a treatment process within the treatment plant. During a bypass, partially treated wastewater and storm water may be discharged. The wastewater treatment plant fully treats as much sewage as possible prior to any bypass, and then provides partial treatment to everything else.

Overflows and bypasses are a last resort measure to prevent basement flooding and damage to treatment processes during severe weather.

  • Complete Form
    Share Share comments or questions on Facebook Share Share comments or questions on Twitter Share Share comments or questions on Linkedin Email Share comments or questions link
Page last updated: 21 Feb 2025, 09:50 AM