Grease Traps and Interceptors


Portland Grease Trap Services

What is a grease trap?

A grease trap or grease interceptor is a receptacle located between a restaurant’s drain line and the sewer line that facilitates the separation and collection of fats, oils and greases (FOG) from restaurant waste water. This prevents the fat, oil and grease from entering the municipal sewer system. If FOG is released into the municipal sewer, it adds additional maintenance and expense to the municipal wastewater systems, which is why local governments require commercial kitchens to have a grease trap installed. Municipalities set a minimum amount of FOG that is acceptable in the water leaving an establishment. If these minimums are exceeded, fines are generally issued.

How do grease traps work?

Grease traps slow down the flow of water coming from drains, allowing the water / grease time to cool. When the grease cools it will coagulate and float to the top. The other, heavier solids, then fall to the bottom. The remaining waste water then passes through the drain line on to the city sewer lines.

Why should I maintain my grease trap?

Proper grease trap maintenance is crucial for having an efficiently operating grease trap. Many problems occur when the levels of collected FOG and solids are not monitored. Common problems that occur are: drain line blockages and back-ups, foul odors, (and even worse) too much FOG being released into the city sewer lines, which can lead to big fines.

How do I maintain my grease trap?

Depending on the size of your grease trap or grease interceptor there are different methods for maintenance and cleanup. Most restaurant customers with larger grease traps have a contract with MRP to pump-out and maintain the grease trap when the FOG fills the trap to the service mark. Another important factor for grease trap maintenance is to keep records of when maintenance procedures are done, such as pump outs, clean outs, etc. Also, staff should be encouraged to not just rinse everything down the drains. When possible, encourage the staff to throw solids and other waste in the trash.

Do not run hot water through the lines to flush out grease and other build up. This can prevent the grease from cooling in the trap and cause grease to be flushed into the sewer lines resulting in fines from the city. Additionally be weary of products on the market that are made up of enzymes and surfactants that simply liquefy the grease to get it out of the grease trap. All this does is cause more issues down stream at the wastewater treatment level due to the eventual coagulation and solidification of this grease. This is the reason many municipalities have prohibited the use of such products.

Metro Rooter & Plumbing provides a complete range of repair and maintenance services, including:

  • Cleaning grease traps and interceptors
  • Pick up and recycling of restaurant oils
  • Drain cleaning and jetting
  • Grease trap repair and replacement
  • In-line video camera inspection


  • Oregon FOG program member
  • We work with all Environmental Compliance Officers in Oregon and Washington
  • Preferred Pumper Program

” Their service is outstanding! “

– Ashley

Make an Appointement

Have a plumbing project?

Contact Us, we’d love to talk with you about your project!

Want to know more?