What substance should be avoided to prevent damage to a septic system?

The reason to avoid harsh chemicals like bleach in a septic system is due to their detrimental effect on the beneficial bacteria that are essential for the proper functioning of the system. Septic systems rely on a balanced ecosystem of bacteria to break down organic waste. When bleach and similar chemicals are introduced, they can kill these bacteria, disrupting the natural decomposition process. This can lead to a buildup of solids in the tank, ultimately requiring more frequent pumping and increasing the risk of system failure.

In contrast, other substances listed, like liquid soap and vinegar, are typically less harmful in moderation and do not pose the same level of threat to the bacterial ecosystem. Natural enzymes are even encouraged because they can help break down waste more efficiently without harming the septic system's health.