Keep our sewer system fat, oil and grease free – for households

Not everything that goes into Guelph’s sanitary sewer system will make its way to the Wastewater Treatment Plant. Fats, oils and grease 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 drain 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?

greasystuffGrease is a common by-product 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
  • Raw sewage overflowing into yards, streets, parks, and bodies of water
  • Potential exposure to disease-causing organisms
  • A penalty or fine under the City of Guelph’s Sewer Use By-law (1996) – 15202
  • An expensive and unpleasant cleanup that often must be paid for by the homeowner

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, oil, and grease free.

What you should do

  • Scrape solidified grease and food scraps from your plates, utensils, pots, pans, food preparation and cooking areas and place into your compost pile or green (organic waste) bag or cart for weekly disposal on your regular collection day
  • Use a paper towel to wipe up grease and dispose of the paper towel in your compost pile or in your green (organic waste) bag or cart
  • Liquid cooking oil (i.e. from a deep fryer) can be poured into a sealable container and dropped off at the City’s Household Hazardous Waste Depot location at 110 Dunlop Drive Gate 2. For more information and hours of operation, please call 519-767-0598 or visit
  • 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

What you shouldn’t do

  • Never pour grease down the sink drains or toilets.

For more information

Contact Wastewater Services with questions (8 a.m. to 4 p.m.) or to report a spill 24/7: 519-837-5629, TTY 519-826-9771.

Print-friendly brochure: Keep our sewer system fat, oil and grease free