Which of the following can negatively impact the performance of a septic tank?

The addition of household chemicals can negatively impact the performance of a septic tank for several reasons. Septic systems rely on a balance of natural bacteria to break down and treat waste. Household chemicals, especially harsh cleaners, solvents, and antibacterial products, can kill these beneficial bacteria, disrupting the natural treatment process. This disruption can lead to the accumulation of solids in the tank, reduced efficiency in breaking down waste, and potential system failure.

In contrast, proper disposal of solids is crucial for the effective operation of a septic system, as is the regular pumping of the tank to remove sludge and scum that accumulate over time. Using the system for wastewater is its intended purpose, and if done appropriately, will not negatively impact its performance. Therefore, the focus on household chemicals highlights the importance of maintaining the delicate ecosystem within a septic tank.