Wastewater Collection System

Sanitary Sewers

The City's sanitary wastewater system is designed to collect and treat wastewater in order to make it acceptable to introduce back into the environment. To protect the health of our citizens and the safety of the environment, we use state of the art technology at all our pollution control centres. The following components are part of the system to convey and treat water used by Londoners:

1,300 kilometres of sanitary gravity sewer
47 kilometres of forcemain
20,000 maintenance holes
43 pumping stations
6 pollution control plants

Sanitary sewers carry wastewater from homes, commercial buildings and industrial sources to one of six wastewater treatment plants. After treatment the water is returned to the Thames River.

We also have over 2,300 metres of combined sewers that convey both wastewater and run-off through the same pipe. During heavy rainfalls combined sewers can become overloaded and may overflow into the Thames River. To address this environmental and financial issue, London has begun a program which aims to reduce the number of combined sewers in the city.

Wastewater discharged into sewers is governed by London's Waste Discharge By-law. Other by-law documents are the Sewer System Charges By-law and Drainage By-Law. To view these pdf file, you need a software program such as Adobe Acrobat Reader. You may also obtain an official copy of these by-laws by calling 519-661-4505.