Fats, Oils, Grease (FOG)


Keep your drains fat-free!

Fats, oils, grease (FOG) comes mostly from pre-rinsing dishes or washing pots and pans in the kitchen. When cooking fat, oil, or grease is allowed to go down the drain, it eventually cools in the wastewater (sewer) system and sticks to pipes creating FOG buildup, also known as a fatberg

Sources of FOG include:

  • Gravy, sauces and soups
  • Cooking oil, butter, shortening, lard and margarine
  • Milk, cream, sour cream and mayonnaise
  • Food scraps
  • Oil from cooked meats

 The buildup causes clogs and backups into homes and businesses, wastewater overflows and spills onto private property, streets, and into local waters.  FOG buildup increases the cost of maintaining Kirkland's wastewater treatment systems and can create serious public health problems. Pipe cleaning companies report that 95 percent of the problems they fix are due to grease.

Fortunately FOG is also a valuable resource. You can recycle your used cooking oil by bringing it to a collection tank at the North Kirkland Community Center, 12421 103rd Avenue NE. A local company, General Biodiesel, collects the cooking oil, converts it to biodiesel fuel and distributes it for use in local fleets.


Information for residents

  • Pour cooled fats, oils, and grease into a container and put the container in the trash
  • Before washing, use your paper napkin or a paper towel to wipe FOG from dishes and dispose of it in the yard waste cart   
  • Use sink strainers to catch food waste   
  • Put food scraps in yard waste cart   
  • Disconnect and stop use of in-sink garbage disposals which flush food and FOG into sewers

Information for restaurants and businesses

Food service establishments generate a significant amount of fats, oil and grease. In 2001, the City of Kirkland passed ordinance 3778 to reduce the accumulation of fats, oil and grease in our wastewater system. The ordinance applies to restaurants and other nonresidential facilities where food is prepared or served and requires them to control FOG with grease traps or interceptors that are cleaned regularly along with other provisions. (See City of Kirkland Municipal Code Section 15.36 for details.)

The City also implemented an inspection program to ensure compliance with the ordinance. The inspector confirms systems are clean and functioning properly and provides information to help improve Best Management Practices (BMPs).

Grease Removal Devices (GRDs) are required

Grease Removal Devices (GRDs) are required in the City of Kirkland. Retention of kitchen waste in grease traps and interceptors allows the grease to separate from the wastewater before it enters the city’s sewer mainline. Grease traps are usually found under or near sinks in your cooking area. Interceptors are usually large underground vaults located outdoors.

You must obtain a permit to install a GRD. For assistance, please contact the City of Kirkland Planning and Building Department at 425-587-3600 or visit their permit process page. A qualified local contractor can help you with the appropriate selection, installation, and maintenance of your GRD.


FOG can cost you money

City of Kirkland Ordinance 3778 requires all food services to install and maintain a grease removal system and use Best Management Practices (BMPs). This ordinance also holds business owners liable for cleanup costs related to a sewer backup. Violations may result in fines and may include water/sewer service shutoff for continued failure to comply.

Install a Grease Trap or Interceptor

Grease interceptors are designed to catch FOG before they get into your sewer. Grease traps are usually found under or near sinks in your cooking area. Grease interceptors are usually large underground vaults found outdoors. Contact a qualified local contractor for help with the appropriate selection, installation and maintenance for your interceptor.

Best Management Practices

  • Educate and train employees about these practices and encourage them to come up with new ideas for controlling FOG

  • Always remove leftover fats, oils, grease and food waste from all dishes, pots, pans and cooking equipment prior to pre-rinsing or washing

  • Remove garbage grinders. Use and maintain strainers in wash, rinse, food prep and floor sinks.

  • Use your trash can for food scraps rather than the pre-rinse sink. Spatulas work well for this. Solid waste can accommodate 10 percent liquid so even your gravies and other oily sauces can be sent to the dumpster. Handle solid waste wisely for health safety: secure trash bags, dump daily, and keep the dumpster lid secured.

  • Install and maintain screens in all floor and sink drains. This will also reduce the amount of food waste that accumulates in your grease interceptor or side sewer.

  • Post "Fight FOG" signs(PDF, 3MB) to remind your staff not to pour used fry grease, hood vent grease, or any other used fats and oils down the sink drain. Contrary to popular belief, adding hot water, detergent or even commercial degreasers does not liquefy the grease long enough to escape your drains.

  • Hire a contractor to properly maintain range vent hoods and filters and dispose of the waste properly

  • Wash all floor mats, grills and greasy kitchen equipment in a sink that goes to your trap or interceptor. Never wash these items outside where the water can flow to a storm drain.

  • Reduce both garbage costs and FOG problems by recycling food, FOG, paper and organic wastes. Contact the Solid Waste Programs Lead at 425-587-3814 for more information.

Periodic maintenance

City ordinance requires weekly cleaning for grease traps and quarterly pumping of interceptor tanks at a minimum. Traps may be cleaned by restaurant employees or others. Interceptors must be cleaned by authorized contractors. Frequently skimming oil and grease from traps saves time and money, and reduces the risk of odors, drain clogs and violations. More than 25 percent buildup of solids and scum layers in a trap or interceptor is a violation of city policy.

Traps (inside) and interceptors (outside) are limited in the amount of grease they hold. More than 25 percent buildup of solids and scum layers in a trap or interceptor is a violation of city policy. The accumulated grease must be disposed of properly. Here is a partial list of companies that pump out and/or recycle your grease trap/interceptor waste.*

*This list is not meant to be all-inclusive. The City makes no recommendations regarding private firms providing fats, oils, and grease (FOG) removal and recycling services.

Maintaining a FOG log

Keep a log of trap or interceptor cleaning. Records should note the dates of cleaning, who did the cleaning, and how much FOG was removed. Records must be available for review by the City inspector and must be kept for a minimum of three years. The FOG log(DOC, 68KB) form is available for your use.

County permits

Food service establishment businesses in King County are required to obtain a permit through the Seattle and King County Department of Public Health prior to operating. Please visit their website for more information.

All dischargers that generate and dispose of industrial wastewater to the King County sewer system must get approval prior to discharging from the King County Industrial Waste Program.