A garbage disposal is an electrically operated device that grinds food waste into extremely small particles, allowing the particles to readily pass through the plumbing with waste water. With a house connected to municipal sewer/waste lines, using a garbage disposal is usually devoid of concerns and rarely causes a second thought. That's not always the case in a house with a septic tank. Municipal sewer lines can easily handle any volume of liquid waste that may exit a household. Septic tanks have a limited volume capacity and require regular upkeep. While a homeowner who has a septic tank can have and use a garbage disposal, there are a few considerations to keep in mind when doing so.
Septic tank capacity
Approximately 25 percent of the homes in North America have septic tanks. Septic tanks typically hold between 1,000 and 2,000 gallons of fluid. When a garbage disposal is used to grind food into small particles that are flushed into the septic tank, it serves to concentrate the suspended solids inside the tank. This can lead to more rapid sludge accumulation.
If a home has already been built, then obviously the occupants are going to have to use the garbage disposal sparingly to avoid prematurely filling the septic tank, which requires more frequent evacuation (pumping). Adding a filter to the septic tank helps prevent solids from causing drain field obstruction. With homes under construction, if you want to put in a garbage disposal, you should increase the holding capacity of the septic tank (as well as the size and composition of the drainage field or leach field) to accommodate the food wastes.
While using a garbage disposal in a home equipped with a septic tank is less than ideal, there are a number of things that you can do every day to help prevent clogs and septic system issues. Never pour oil or grease into the garbage disposal, especially grease from meat. Potato peels and fibrous materials such as artichokes can block the flow of fluid into the leach field.
Caustic chemicals and disinfectants can damage the septic tank as well as the drain field. Try not to allow bleach or other chemicals down the garbage disposal. Since garbage disposal use generally increases the volume of material entering the septic tank by as much as 50 percent, try to use the garbage disposal as sparingly as possible. You can buy a number of additives that contain bacteria that are specifically designed for septic tanks. Consider buying an additive and following the usage instructions on the package. The additive will help speed up the decomposition of food particles in the septic tank.
The addition and use of a garbage disposal is going to cause the septic tank to fill up faster, so the tank will have to be pumped more frequently than would be necessary without the garbage disposal. With heavy disposal use, you may need to pump twice as often. Since septic systems require a fair amount of property due to the drain field, consider composting waste produce instead of using the disposal. This will help reduce disposal usage.