The Guelph Wastewater Treatment Plant (WWTP) provides treatment of domestic, commercial, institutional and industrial wastewater collected from the City of Guelph and the neighbouring community of the Township of Guelph/Eramosa. The facility, located at 530 Wellington Street West, provides tertiary treatment with disinfected effluent being discharged to the Speed River.

The WWTP provides preliminary screening and grit removal, primary treatment by sedimentation, secondary treatment by conventional and extended aeration activated sludge and two stage tertiary treatments utilizing rotating biological contactors (RBC) followed by sand filtration. Disinfection of the final effluent is a requirement and is accomplished by the addition of sodium hypochlorite followed by the addition of sodium bisulphite for de-chlorination prior to discharge to the receiving stream.

Contact information

530 Wellington Street
Guelph, ON
Monday to Friday 8 a.m. – 4 p.m.
519-822-1260 extension 5629
Fax: 519-837-1226
Business: 519-837-5629
After hours emergency: 1-866-630-9242


As of June 19, please use ON1Call to request locates
for any activity that involves digging

This includes, but is not limited to:

  • Building decks and fences
  • Installing pools
  • Paving or laying driveways
  • Planting trees
  • Creating new gardens
  • Installing light standards

Visit on1call.com or call 1-800-400-2255 for more information.

The locate request service does not replace the need for building and other permits for the same types of work. Permit requests are still administered by Building Services Visit guelph.ca/building for more information.

Help keep Guelph’s sewer system fat-free

Not everything that goes into Guelph’s sewer system will make its way to the Wastewater Treatment Plant.Fats, Oils and Grease, also known as FOG that are poured down the drain or flushed down the toilet can stick to your home’s sewer pipe. Grease cannot be broken down effectively during the wastewater treatment process and cold weather solidifies grease. Just like a steady diet of greasy food can clog your arteries, grease flushed down the pipes blocks sewers. Over time, grease can build up and eventually block an entire pipe, surging up through sinks, floor drains and toilets causing sewage backups and overflows that can cause health hazards, damage home interiors and threaten the environment.

Where does the grease come from?

Grease is a common byproduct of cooking and is found in items such as:
  • Butter and margarine
  • Cooking oil
  • Dairy products
  • Food scraps
  • Lard and shortening
  • Meat fats
  • Sauces

What are the results of a sewer blockage from your home?

A sewer blockage caused by grease accumulation in your home’s sewer pipes may result in:
  • Raw sewage overflowing into your home or your neighbours’ home;
  • An expensive and unpleasant cleanup that often must be paid for by the homeowner;
  • Raw sewage overflowing into parks, yards, streets, and bodies of water;
  • Potential exposure to disease-causing organisms;

What you can do to help

The easiest way to prevent household and environmental damage caused by sewer overflows and backups is to make sure our sewer system is fat-free.

How to dispose of grease properly

  • Never pour grease down the sink drains or toilets.
  • Solidified grease can be scraped into your Wet bag.
  • Liquid cooking oils (e.g. from a deep fryer) can be poured into a container and dropped off at the Household Hazardous Waste Depot.

Tips for keeping Guelph’s sewer system fat-free

  • Scrape solidified grease and food scraps from your plates, utensils, pots, pans, food preparation area and cooking area into your Wet bag or compost pile.
  • Place a strainer in your sink to catch food scraps and other solids. Dispose of grease and food scraps in your Wet bag or compost pile.
  • Use a paper towel to wipe up grease and dispose of the paper towel in your Wet bag or compost pile.
  • Be careful when using a commercial cleaner or detergent which claims to dissolve grease as they may only transport the problem further down the sewer system.
For more information contact the Wastewater Treatment Plant at 519-837-5629 or e-mail wastewater@guelph.ca.

For After Hour Emergencies call 1-866-630-9242.