How Fat, Oil and Grease Effects the Sewer System

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Cut away from a clogged sewer pipe that is full of grease

A video was taken in January 2014 of a sewer lateral pipe that runs from a house to the sewer main below the street in a Niagara Falls residential neighbourhood. Fats, oils and grease when flushed down the drain, build up in the lateral, and restrict the flow from your house. This can result in sewage back-ups in your home.  This also adds to grease to the sewer main – which may impact numerous houses, and effect the functioning of the City’s sewer system.

There is another video of a City sewer main that runs below the road.  Fats, oils and grease build up in the sewer main, and solidify.  This material is very hard, and is difficult and costly to remove.   This calcified material can restrict the flow of water, and combined with a snow melt or rain storm, may result in sewage back-ups in the home.

How do fat, oil and grease cause sewer blockages?

When warm fats, oils, and grease are washed down the sink or toilet into the plumbing system they cool, harden and stick to the inside of sewer pipes (both in private sewer lines in your home and City sewers under the streets). Over time, the grease will build up and can block the entire pipe.

Where do fat, oil, and grease come from?

They often are a result of cooking, and can be found in meats, fats, lards, cooking oil, shortening, butter and margarine, food scraps, baking goods, sauces, salad dressings and dairy products.

What is the result of fat, oil, and grease build-up in the sanitary sewer systems?

You may think that once it’s gone down the drain, it simply washes away and is gone for good. But that’s not the case. Fat, oil and grease can build up in your pipes, causing blocked sewers which can lead to problems, such as:

  • Overflowing of raw sewage into your home, business, or neighbouring property, causing basement flooding – an expensive and unpleasant clean-up
  • Contact with disease-causing organisms
  • Raw sewage overflow into parks, yards, streets, creeks, rivers and the lake
  • An increase in operation and maintenance costs to clean and repair damaged sewer pipes.

What can you do to help prevent sewer system blockages?

  • NEVER pour grease down sink drains or into toilets.
  • DO put basket/strainers into sink drains to catch food scraps and other solids. Empty the drain basket/strainer into the Green Bin for disposal.
  • Please note that depositing any matter capable of obstructing the flow of, or interfering with the operation of, a sewer is enforceable through the Region’s Sewer By-Law – 47-2008.

What should you do with your fat, oil and grease?

  • Let the grease cool and harden, then scrape it and food scraps from trays, plates, pots and pans, utensils, grills, and cooking surfaces into your Green Bin.
  • Small volumes of liquid cooking oil can be placed into the Green Bin as long as the oil can be absorbed by the other organic materials or paper towels.
  • Larger amounts should be collected into a sealed container labelled “cooking oil” and can be dropped off at household hazardous waste depots on community environment days. See the Niagara Region’s site for more information.

What is the City of Niagara Falls doing to address the problem?

The City regularly inspects sewer mains, and cleans with high pressure or mechanical devices. Typically, the City inspects all sewer mains once every five years. Additionally, sewer mains are video inspected to determine the condition of the pipe at the time.

In some areas, a more frequent cleaning schedule is required to remove accumulated grease and debris that is in the main. Sometimes – grease and debris completely block the sewer main – resulting in sewer back-ups to home.

The City responds immediately to clear the main and blockage. In freezing temperatures, this incrusted grease is almost impossible to remove, and high pressure equipment freezes making removal a difficult task. Mechanical methods can be used to dislodge stubborn incrustation, but this can be damaging to the sewer mains.

If during the process of investigation, any structural defects are found, the City immediately schedules repairs to sewer mains or laterals, to fix the problem.