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Sewer Maintenance
909 East Sprague Avenue 99202
Phone:(509) 625-7900
Fax:(509) 625-7940
Riverside Park Water Reclamation Facility
4401 N. A.L. White Parkway 99205
Phone:(509) 625-4600
Fax:(509) 625-4605
Treatment Plant

What is FOG?

FOG stands for Fats, Oils, and Grease that get into the sewers and cause problems for the wastewater treatment system. It comes from:

  • Salad Dressings
  • Gravy and other sauces
  • Cooking oil
  • Animal fats
  • Milkfat

Here is a video about FOG produced by Channel 5 Cable News.

How does FOG get into the sewer?

Any oily or greasy waste that gets into the sink or drain goes to the sewer. Common sources include:

  • Rinsing cooking equipment and dishes in the sink
  • Cleaning exhaust hoods and filters in the sink
  • Dishwashers discharging water over 140° into grease traps
  • Poorly maintained grease traps or interceptors

What's the problem with FOG?

FOG is the number one cause of sewer blockages. It solidifies on the walls of sewer pipes and can cause clogs that interfere with normal flow, resulting in:

  • Sewage spills
  • Manhole overflows
  • Sewage backups into businesses
  • Clog cleanout by sewer maintenance personnel
  • Higher sewer rates

How can you keep FOG out of the pipes?

Basically, the less FOG that goes down the drain, the less that gets into the pipes. Simple ways of reducing the amount of FOG going down your drains include:

  • Display FOG information in the workplace—click here for printable FOG poster.
  • Collect used oil and grease for recycling or disposal in solid waste.
  • Dry scrape dishes into a trash bin, not the sink.
  • Prevent spills. When spills happen, clean up with disposable materials (paper towels, kitty litter, spill kit), don’t wash down the drain.
  • Clean and cover outdoor recycling areas.
  • Hire a waste-hauling or recycling service to regularly pump out your interceptor.
  • Keep records of cleaning and service to track how often grease traps need to be maintained.
  • Don’t connect dishwashers to the grease system.
  • Train staff to keep FOG out of pipes—click here for printable fog information.

What about grease traps and interceptors? Shouldn’t they keep the grease out of the pipes?

Every food preparation establishment is required to have a grease trap or interceptor. There are three types: passive grease traps that are usually located under the sink and must be cleaned out by hand; automatic grease traps that continually skim grease off and deposit it in a removable reservoir; and grease interceptors that are large volume devices, usually located outside, under the ground and must be pumped out by a grease hauler. These devices are very important but they can’t do the job alone:

  • Traps vary in efficiency, some remove only 85% of FOG
  • Passive grease traps should be cleaned out weekly
  • Automatic grease traps should have their collection reservoirs emptied daily
  • Grease interceptors need to be pumped out regularly, on a schedule determined by how quickly they fill. When over 25% of the interceptor is full of grease the interceptor loses effectiveness; at 50% the interceptor lets most of the FOG flow through into the sewer.
  • Keep records in a log of when traps and interceptors are cleaned out and how full they are each time. This way you can know how often they need to be maintained.
  • The less FOG that goes down the drain, the less frequently the traps need to be cleaned out.

Helpful websites from other municipalities:

Grease trap maintenance fact sheet from Contra Costa County, California
http://www.centralsan.org/documents/Grease_Trap_Maint_Fact_Sheet.pdf

Restaurant checklist for FOG control from City of Lakeport, California
http://www.cityoflakeport.com/docs/FOG---FSE-Assessment-Checklist-716200894323PM.pdf