Sanitary sewer cleaning

Routine maintenance keeps Guelph’s sewer pipes flowing

A truck with the City logo is parked in the roadway. Staff in safety clothing are lowering a large tube into a sewer hole in the roadway from which the cover has been removed. There are safety pylons around the truck.The City completes sewer main cleaning across Guelph on about a three-year rotating basis.

Cleaning is done year-round, Monday to Friday between 7 a.m. and 5 p.m., and usually takes a few hours on each street.

We are currently cleaning sewer mains in areas 68, 71, 78, 79 and 87 during the month of September.

What to expect

  • Toilets, sinks and other appliances can still be used during cleaning.
  • Air pressure in the sewer can create noise in sewer pipes, and may cause water to splash out through toilets, sinks and drains. Keeping toilet lids closed, and sink drains plugged when not in use will help avoid spills.
  • Sewer cleaning can create short-term nuisance odors. Odors can be cleared by opening a window for a few minutes, and running water down sink and bathtub drains, flushing toilets, and pouring a pail of water into basement floor drains.
  • No chemicals are used in sewer main cleaning. High pressure water is used to loosen debris and flush pipes. A high-powered vacuum then removes debris from the pipe, and it’s transported to the City’s Wastewater Treatment Plant for processing and disposal.

What are sanitary sewer mains?

Everything you flush down your home’s toilets and sinks goes to the sanitary sewer main. This includes wasted water from water-based appliances such as dishwashers and clothes washers. Sanitary sewer mains carry this waste to the wastewater treatment plant where it is treated before flowing into the Speed River.

Why we clean sewer mains

Sewer main cleaning helps prevent blockages and backups by removing build-up in the mains including tree roots, grease, grit and sand. This important maintenance work keeps our sewer mains flowing, reduces the potential for nuisance odours, and helps protect our infrastructure.

Sewer main cleaning is also done for CCTV inspection work.  These inspections allow us to see the condition of our sewer mains and make necessary repairs or replacements.

We apologize for any inconvenience during this important maintenance work. Your patience is greatly appreciated.

How you can help

You can help prevent blowbacks and odours in your home by:

  • Occasionally adding water to sink and floor drains to prevent sewer gases from entering your home
  • Checking your plumbing vents each spring and fall for blockages (e.g. bird nests or leaves)

You can also help keep the City’s and your home’s sewer pipes free from blockages by using sinks and toilets properly.

  • Fat clogs sewer pipesDon’t use your toilet or sink as a garbage can. Dispose of garbage, household hazardous waste, medications and all food items, especially grease and oil, properly. Get tips on proper garbage disposal at
  • Don’t flush those “flushable” products. Flushable wipes and other such products don’t biodegrade and can lead to blockages in sewer pipes.

More tips

For more information

Wastewater Services