Protecting Your Sewer from Fats, Grease and Oil

Fats, oils and greases aren’t just bad for your arteries and waistline, they’re bad for your sewer too. 

Sewer overflows and backups can cause health hazards, damage home interiors and threaten the environment. An increasingly common cause of overflows is sewer pipes blocked by grease.

Grease gets into the sewer from household drains as well as from poorly maintained grease traps in restaurants and other businesses. But helping prevent sewer overflows and backups is easy.

Where does the grease come from?

A byproduct of cooking, grease comes from meat fats, lard, oil, shortening, butter, margarine, food scraps, baking goods, sauces and dairy products. When washed down the sink, grease sticks to the insides of sewer pipes on your property and in the streets. Over time, it can build up and block the entire pipe.

Beware: Home garbage disposals do not keep grease out of the plumbing system. Products such as detergents that claim to dissolve grease might pass it down the line and cause problems elsewhere, possibly resulting in the following:

  • The overflow of raw sewage in your home or your neighbor’s home.
  • An expensive and unpleasant cleanup that often must be paid for by you, the home or business owner.
  • The overflow of raw sewage into parks, yards and streets.
  • Potential contact with disease-causing organisms.
  • An increase in operation and maintenance costs for local sewer departments, which causes higher sewer bills for customers.

What You Can Do

The following are ways you can help prevent sewer overflows:

  • Never pour grease down sink drains or into toilets.
  • Scrape grease and food scraps into a can or the trash for disposal for recycling (where available).
  • Put baskets/strainers in sink drains to catch food scraps and other solids, and empty them into the trash.
  • Talk with your friends and neighbors about how to keep grease out of sewers.

What Business Owners Need to Know

For a grease trap or interceptor to work correctly, it must be properly:

  • Designed, sized and manufactured to handle the amount that is expected
  • Installed properly – must be level and vented
  • Maintained – cleaned and serviced on a frequent basis

Solids should never be put into grease traps or interceptors. Routine daily maintenance of grease traps and interceptors is necessary.

Information adapted from the Water Environment Federation.