The Interaction Between FOG And Septic Systems

Posted on: 23 October 2019

Fats, oil, and grease (FOG) are some of the worst substances you can introduce into your septic system. Below are some of the details you should know about FOGs in septic systems:


A typical household uses considerable amounts of FOG products, a lot of which can end up in the septic system if care is not taken to prevent it. Here are some of the main sources of FOG in the septic system:

Cleaning Chemicals

Many cleaning products contain considerable oil and grease. You introduce FOG into the septic system whenever you use cleaning chemicals to clean your floors, windows, or utensils and let the waste flow down the drain.

Food Remains

Food remains are some of the biggest sources of FOG. They come in the form of vegetable oils and animal fat, which many people use to cook or fry food. Grease trapped in cooking or eating utensils also ends up in the drain during cleaning.

Bath Products

Many bath products also contain FOG. Bath soaps, hair conditioners, cleaning gels, moisturizers, among other bathroom products, usually end up down the drain.


The effect of FOG in the septic system increases with the nature and amount of fog. Here are the two main consequences you need to worry about:


Some forms of FOG, such as grease, don't flow down the drains as efficiently as other septic wastes. Some, such as fats, can even clog and get trapped within the drains. When other solid particles meet the trapped FOG within the drainage pies, blockage occurs that can lead to slow drains or even back up of wastewater into the house.

Clogging can also occur in the septic drain field. This is because some of the FOG may end up, in their raw form, in the septic drain field. Such FOG won't seep into the soil, and they might also block further absorption of the treated wastes. The result is that your septic drain field might flood.

Treatment Inefficiency

FOG in the septic tank doesn't get broken down as easily as other forms of waste.  The more FOG you send into the septic tank, the more the tank will hold untreated wastes. This will create a huge layer of solid scum in the tank, further increasing the system's ability to treat its wastes. You will need to pump your tank more frequently than normal to get rid of the accumulated wastes.

Hopefully, you will be able to keep FOG away from your septic system. If your septic is already suffering under the weight of FOG, consult a service like Sound Septic Pumping and Services, Inc to clean the system and get it running efficiently again.