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1 NW Martin Luther King Jr Blvd
Civic Center Complex, Room 104
Evansville, IN 47708
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Managing Fat, Oil and Grease (FOG)

What is FOG?


Photo source: Arlington County

Fat, Oil and Grease (FOG) are found in many foods and cooking products. After a meal, plates and pans may be covered with leftover food, cooking oils and grease.

If plates and pans are not wiped clear of FOG before being put into the dishwasher or sink, the fat, oil and grease end up getting washed down the drain. This is where the trouble begins.

FOG collects in sewer lines and forms large clogs that may lead to costly, destructive sewer backups that can damage homes, streams and wetlands.

What can I do?

Reducing FOG in sewer lines is easy, and everyone can help.

After every meal, wipe leftover food and cooled fat, oil and grease from your plates and pans into the trash before dish washing.

Clean-up tips:

Collecting FOG: It is better to put FOG into the trash than down the drain, but FOG should be collected and sealed properly before disposal. Having a small metal (or other durable material) container handy, such as a tin can, will make FOG collection and disposal safe, easy and effective.

  • Scrape/pour FOG into the container
  • If still warm, allow FOG to cool completely
  • Stuff can with a paper towel to contain the FOG
  • Seal the container in an old, used ziplock bag or with plastic wrap
  • Throw container into the trash

To remove a portion of FOG while preparing oily or greasy food: Tip frying pan slightly to one side to allow FOG to pool in one spot. Use a tablespoon to scoop up the FOG and place it into metal container. Allow FOG to cool completely, and seal can before disposing.

To remove excess FOG from foods like bacon: Place the food on a plate covered with a paper towel and blot the food with a paper towel or napkin to remove excess grease.

For foods like ground meat: Place a colander into a bowl and then put the cooked meat into the colander. Press the meat with a paper towel to force the excess oil or grease into the bowl. Pour the oil or grease into a small metal container and allow it to cool completely. Seal container as described above and discard into the trash.

Liquid cooking oil: Allow the oil to cool and pour/scrape it into a small metal container. Seal container as described above and discard into the trash.

Grease after frying: Allow the grease to cool and pour/scrape it into a small metal container. Seal container as described above and discard into the trash.

Grease in cooking water: Allow water to cool. Skim off the grease floating on the surface of the water, and place it in a tin can or on a paper towel. Discard grease into the trash.

Don't rely solely on dishwashing liquids

Contributing to the problem of FOG are dishwashing liquids. These products break up (disperse) fat, oil and grease in the sink or dishwasher. Unfortunately, this simply moves the FOG problem down the line. Dispersed fat, oil and grease recombine in the sewer.

Remove as much FOG from plates and pans before washing.

Become a FOG detective

All may seem tranquil in our town, but a thick FOG is forming. Beneath our homes and streets, a growing menace lurks, gathering strength, preparing to steal our peace.

Quietly, fat, oil and grease (FOG) flow from our kitchens and into our sewer pipes, forming destructive clogs that block sewers and threaten our homes, streams and wetlands with sewer spills and backups.

On the case—protecting our homes and wetlands—are super sleuth FOG detectives. This muskrat and otter duo fearlessly searches for clues and uncovers the sources of FOG in our homes.

Be a hero by becoming a FOG detective, too. Help clear the FOG and save our town!

Finding the hidden FOG

Recognizing the sources of FOG is generally easy—cooking oils; fat trimmed from beef, chicken and turkey; fatty meats like bacon; and greasy pizza.

But FOG has some surprising forms:

  • Milk and yogurt (containing fat)
  • Cheese
  • Peanut butter
  • Salad dressing
  • Mayonnaise

Please don’t put foods containing fat down the drain. Read the product label. If it is meat or contains fat, it is a source of FOG.

FOG costs us all

As FOG collects in sewer lines, the risk of sewer backups increases. FOG narrows the available space for water and sewage to pass. If the system is quickly loaded, like after a heavy rain, the downward flow of sewage can suddenly stop, causing it to reverse direction. Sewage then finds the pathway of least resistance, which is typically into lower levels of homes, onto streets and into nearby streams.

  • Sewer backups are messy, costly and destructive
  • To keep up with accumulating FOG, the utility company must clean sewer lines, sanitary manholes and lift stations regularly, which may increase customers’ utility rates
  • Reducing or eliminating FOG reduces sewer cleaning costs, which can reduce rate increases

Sewer backups can flow into streams and wetlands, impacting wildlife and damaging the environment!

FOG costs us all

Our marshes, streams and wetlands are extremely precious and valuable areas. This vital buffer zone between waterways and land improves natural water quality, protects against flooding and shoreline erosion, and provides habitats for numerous species of microbes, plants, insects, amphibians, reptiles, birds, fish and mammals native to southern Indiana, including the muskrat and the otter.

Muskrats and otters are aquatic mammals and are well suited for fresh water living. They spend their entire lives living next to and in ponds, marshes, streams and lakes. It is well known that river otters are excellent swimmers, with big, webbed feet and long, slim bodies, but they are also very keen hunters of their favorite foods (crustaceans, mollusks, insects, crayfish, frogs, turtles and aquatic invertebrates). These keen hunting skills make them excellent FOG detectives.

Muskrats are also excellent swimmers. Believe it or not, muskrats can even swim backwards! However, muskrats love to follow trails, which is why they can often be found hot on the trail of sources of FOG.

Wetlands offer robust benefits to man, but their health can be significantly impacted by man’s activities. The relationships between the plants, animals, fish and insects of the wetlands are extremely complex, and events like sewer backups and overflows can disrupt this complex system for long periods. We must all work together to protect our wetlands.

Every drop matters

It’s easy to think that putting a little grease down the drain now and then can hardly matter, but in reality, it does. That’s because our sewer system is a network of pipes, manholes and collection areas connected to hundreds of thousands of households and businesses. Small amounts of fat and grease deposited into sewer lines day after day across the entire network add up quickly.

Consider an area the size of Vanderburgh County with the population of about 180,000. If one tablespoon of fat, oil or grease is put down the drain per person per day, 15,400 gallons of FOG can accumulate in just 22 days.

That’s enough to fill an average home swimming pool!

Managing Commercial Fat, Oil and Grease

The National Pretreatment Program seeks to reduce and eliminate the amount of Fat, Oil and Grease (FOG) from food service establishments (FSE). These pollutants are known to cause obstruction in collection systems.

For questions about grease trap design, maintenance or function please contact: Matt McBride, FOG Coordinator, Evansville Water and Sewer Utility, (812) 436-7013 or mmcbride@ewsu.com

Grease trap cleaning isn't difficult, but it can be inconvenient and time-consuming. If you do not want to do this work yourself, professional grease trap cleaning will ensure that your equipment lasts as long as possible with high functionality.

The following links offer valuable information regarding best management practices for managing food materials, grease trap design, maintenance, function and go-green initiatives. Furthermore, the EWSU Water and Sewer Manual is provided as a guide for the planning, design, and construction of sanitary sewer collection systems and water distribution systems and related facilities for projects that are initiated by private entities such as land developers, private property owners or other such parties, and that require EWSU approval and/or acceptance.

National Pretreatment Program - Controlling Fat, Oil, and Grease

Policy for Design, Installation, and Maintenance of FOG Removal Systems

Water and Sewer Manual