What material should be avoided in a septic system?

Cooking oil should be avoided in a septic system because it can cause significant issues with the system's functionality. When cooking oil is introduced into the septic tank, it can solidify and form clumps, creating blockages in the plumbing and preventing proper flow within the system. This can lead to backups, overflows, and ultimately costly repairs or replacement of the septic system.

In contrast, human waste and paper products are typical components designed for breakdown in a septic system. Bacteria additives may also be used in some cases to enhance the breakdown of organic matter, but excluding cooking oil is crucial to maintaining the health and operation of the system.