Fats, Oils & Grease (FOG)


FOG stands for fats, oil and grease. Two types of FOG pollutants are common to wastewater systems:

  • Petroleum-based oil and grease (nonpolar fats), which typically occur at auto-related businesses.
  • Animal and vegetable-based oil and grease (polar fats), which are commonly found in food ingredients such as meat, fish, butter, cooking oil, mayonnaise, gravies, sauces and food scraps.

The Problem

When fats, oil, and grease enter the sewer system, the substances build up along the pipes, which can cause sewage backups and overflows, as well as extensive building and property damage.

How to Help at Home

  • Pour fats, oils & grease into a covered disposable container — such as glass, plastic or a sturdy zip-top bag.
  • Store it in the freezer and then put it in the trash after it has hardened.
  • Use paper towels to wipe greasy dishes before washing. Put the paper towels in your food waste.
  • Use sink strainers to catch food waste when washing.
  • Put food scraps in compost bin or in the trash.

Requirements for Business

  • Review section on Fats, Oils and Grease in City code.
  • New businesses that add fats, oil and grease into the sewer system must install and maintain grease control devices.
  • Businesses must implement best management practices (BMPs).
  • Employees are required to be trained on FOG BMPs.
  • All kitchen staff must be trained every six months. The city will provide training materials upon request.
  • Businesses must submit a maintenance log to the city annually, by Dec. 31 each year, to document that maintenance is being performed on grease traps (PDF) and grease interceptors (PDF).

Who Must Meet These Requirements?

Any businesses that add fats, oil and grease into the sewer system — and are served by the City of Issaquah sewer utility — would be required to meet these regulations. View a map of the City's service areas (PDF).

How Do I Maintain My Grease Interceptor or Trap?

Many contractors specialize in maintenance, installation, and repair of grease pre-treatment devices or provide recycling services for grease oil. Seattle Public Utilities has prepared this list of local contractors (PDF) who provide these services. You can also check the yellow pages or search the web for local companies.