Under the City of Toronto Sewers By-law, it is mandatory for establishments that cook, heat, process or prepare food on-site to install, operate and maintain a grease trap (interceptor) on any pipe that connects directly or indirectly to a sanitary sewer system.

Facilities that must install a grease trap include:

  • Food service establishments (i.e. restaurants, coffee shops, banquet halls, etc.)
  • Child care centres
  • Mobile food vendors

Not having a grease trap installed or working properly can result in conviction and fines of up to $100,000. A full list of requirements can be found in the Food Service Establishment (FSE) Environmental Code of Practice.

A grease trap, also called an interceptor, is a plumbing device designed to “trap” and prevent fat, oil and grease from entering the sanitary sewer system.

Fat, oil & grease (FOG) is commonly generated when cooking, processing and/or preparing food and can be found in several items such as food scraps, butter, margarine, sauces and salad dressings.

How grease traps work

Grease traps should be connected to any fixture or drain that discharges wastewater containing FOG, including sinks for washing dishes and drains serving self-cleaning exhaust hoods and cooking equipment. Once wastewater enters the grease trap:

  • The FOG cools, hardens and floats to the top of the trap.
  • The rest of the wastewater flows through the trap and out the exit pipe to the sanitary sewer.
  • FOG and any solids settle and remain in the trap.

Facilities must pump out a grease trap at least once a month by a Ministry of the Environment, Conservation and Parks certified waste hauler, as per the Food Service Establishment Environmental Code of Practice.

When warm fats, oil and grease make their way into the plumbing system, they cool, harden and stick to the inside of sewer pipes. Over time, FOG will build up and cause a number of problems, including blocked sewers on your property or the City’s property. This can lead to:

  • Sewage back-ups into your business, neighbouring properties or even local rivers – an expensive and unpleasant pollution clean-up.
  • Increased vermin and contact with disease-causing organisms, all of which pose serious health risks to anyone working in or visiting your establishment.
  • Temporary or permanent closure of your facility by Toronto Public Health.
  • Increased operations and maintenance costs due to cleaning and repairing damaged sewer pipes.

Costs incurred by the City as a result of a grease-blocked sewer will be charged back to those responsible.

  • Post signs stating, “No fat, oil or grease down the drain” throughout the kitchen.
  • Use scrapers and/or paper towel to remove food solids and grease from pots, pans and wares before washing. Dispose of food solids in the green bin.
  • Install and maintain screens over all sinks and floor drains to capture food solids. Dispose of collected food solids in the green bin.
  • Keep cooking oil out of drains. Waste oil can be sold to rendering facilities.
  • Use absorption material to soak up FOG spills on the kitchen floor and under fryer baskets. Dispose of soiled material in the green bin or garbage (depending on the absorption material used, e.g. paper towel, rag, etc.).
  • FOG from exhaust system filters and hoods should be recycled or soaked up using absorption material and disposed of in the green bin or garbage.
  • Do not discharge hot water into the grease trap as this may melt the FOG or displace the contents of the grease interceptor, where it can harden and block your drain line.
  • Do not add any enzymes or other additives into the grease trap as they will only move FOG down the sewer pipe where it could harden and block the pipe.
  • Do not use garbage disposers or grinders as liquefied food waste will fill up the grease trap quicker, leading to more cleaning.
  • Use low-phosphate content, water based cleaners.
  • Use watertight outdoor receptacles of adequate size that are not easily tipped over.
  • Ensure recycling barrels and containers for transporting oil are covered and secured from spillage or tipping over.
  • Ensure FOG and wastewater does not enter the catch basin/sewer grate outside. This includes:
  • Anything other than stormwater entering a catch basin is considered a spill. Should this occur, call 311 immediately.
  • Use an approved Ministry of Environment, Conservation and Parks (MECP) flusher truck to flush any grease blocked lines and vacuum (or suck up) the contents on privately owned plumbing/sewer pipes.

Trap cleaning

  • Clean the grease trap before the grease and solids, combined, reach 25% of the trap’s liquid volume or every four weeks, whichever is earlier. A cleaning frequency of every eight weeks is permitted under certain circumstances (see section 7.1, FSE Environmental Code of Practice).
  • Manual cleaning is only permitted where the establishment generates a low volume of FOG and has no stove or fryer (i.e. mobile food vendor assembling food):
  • Where applicable, clean the gravity grease interceptor (large in-ground passive interceptor) before the FOG and solids exceed 25% of the wetted volume of the tank.

Grease disposal

  • Use an approved Ministry of Environment, Conservation and Parks (MECP) waste carrier to pump-out and clean the grease trap. These companies must provide operational information on the grease trap, including level of FOG and solids estimate, proper maintenance frequency estimate, condition of the grease trap and waste destination.
  • Operators cleaning the grease interceptor in-house must log the cleanings and dispose of the fat, oil and grease in the Green Bin.

Mobile food vendors include:

  • Hot dog vendors
  • Ice cream trucks
  • Food trucks that prepare and/or serve food

How to dispose of wastewater

  • Wastewater must be stored on-site in a separate container from the clean (potable) water and labelled dirty/wastewater water.
  • All wastewater must be poured slowly down an indoor sink/drain (sanitary sewer) that is attached to a grease trap.
  • The grease trap will separate the fat, oil and grease from the wastewater, before sending the wastewater to the sanity sewer.
  • If a mobile food vendor has a grease trap that is connected to a two compartment sink used for washing utensils, then the wastewater that passes through the grease interceptor and flows into the wastewater tank can be transported and poured down any indoor sink/drain (sanitary sewer).