Commercial Fats, Oils & Grease (FOG) Program

Problems caused by wastes (fats, oils & grease) from restaurants and other grease-producing establishments have served as the basis for ordinances and regulations governing the discharge of grease materials to the sanitary sewer system. This type of waste has forced the requirement of the installation of preliminary treatment facilities, commonly known as grease traps or interceptors.

Determine if you need to install a grease trap or interceptor with the following FAQs. A brochure is available for download in English (PDF, 360KB) and Spanish (PDF, 331KB).

What is a grease trap? How does it work?

A grease trap is a small reservoir built into the wastewater piping a short distance from the grease producing area. Baffles in the reservoir retain the wastewater long enough for the grease to congeal and rise to the surface. The grease can then be removed and disposed of properly as mentioned below.

Do I have a grease trap?

If you are not sure, please contact the Clean Water Services at (503) 681-3600 or the Washington County Public Health Department at (503) 846-8722 for assistance.

Do I need a grease trap?

If you use oil and grease OR you cook greasy food in your establishment and they are washed into the sanitary sewer system, you should have a grease trap or interceptor.

What if I don’t install a grease trap?

If you are a restaurant owner and use oil or grease in your food preparation, you will eventually have a maintenance problem with a plugged building sewer line. This blockage can create a sewer backup situation and ultimately a health problem in your restaurant. Someone will have to pay for removing the blockage. If the problem is in your building sewer line, then you will have direct responsibility for paying to remove the blockage or restriction. Contact your local jurisdiction. Their staff will visit your site and assist you in establishing proper grease trap maintenance intervals. If the blockage or restriction is in the public sewer main and it can be proven that you are the cause of the blockage, you are in violation of the Clean Water Act. Enforcement action can be taken and you may also have to pay for the public sewer to be maintained.

What if I don’t choose to help?

The rules of the Health Department, Clean Water Services and the Oregon State Plumbing code will assist you in making the correct decision. Oregon State Plumbing Code states that a grease interceptor may be required by the administrative authority. Clean Water Services is the administrative authority in this case, and the District prohibits the discharge of materials that can solidify and create blockage problems in the sewer system or the treatment plants. The Health Department makes periodic inspections to see that no health problems exist due to improperly maintained grease traps. These rules will be enforced if a problem exists.

What is the criteria for grease trap inspections?

All restaurants suspected of causing problems to the collection system or treatment facilities will be inspected. The grease trap shall be inspected using the following criteria: If the trap is in Fair condition, you will be advised that you may need to keep an eye on the maintenance schedule. You may need to increase the cleaning frequency. If a trap is found to be in Poor condition, you will be issued a compliance order to have it cleaned immediately. You will be required to contact the issuing authority within 30 days to have them verify that the grease interceptor has been properly cleaned. It is extremely difficult to formulate exact criteria for sizing grease interceptors because of the many variables that exist. Where one restaurant may burn grease it has collected, another may use a grill and collect its grease for disposal. No two are operated in a like manner. It is important that the method of operation employed be evaluated prior to determining the size of the grease trap. If you have questions, contact your city sewer maintenance, the Washington County Public Health Department at (503) 846-8722 or Clean Water Services at (503) 846-8931.

How can I be sure I am in compliance with the rules?

Contact your local City Public Works Department, Clean Water Services or the County Health Department. They will inspect your facility and provide technical assistance if necessary.

When and how do I clean a grease trap?

The following procedure is recommended:

All grease traps should be cleaned at least twice each week. Some establishments will find it necessary to clean their traps more often than twice per week. If you are having to clean it too often then maybe you should think about installing a larger trap.

• Bail out any water in the trap to facilitate cleaning.
• Dip the accumulated grease out of the trap. Be sure to scrape the sides and the lid.
• Deposit the grease in a watertight container and have a rendering/tallow company pick it up.

DO NOT...

• Flush out the trap with hot water.
• Rely on drain cleaners, enzymes or bacterial agents. They merely soften the grease and transfer the problem down stream.

Remember...

If you have a grease trap, maintain it properly. Work out a specific cleaning schedule right for you and your establishment. All grease traps need to have the separated grease cleaned out periodically and no one likes to do it. It is a dirty job. Running extremely hot water down the sewer drain only moves the problem down stream. It does not go away. Catch the grease at the source to protect public health and the environment!