How can heavy rainfall affect the performance of a septic system?

Heavy rainfall can significantly impact the performance of a septic system, particularly by saturating the ground around the drain field. When the soil becomes overly saturated, it can reduce the soil’s ability to absorb and treat wastewater effectively. This saturation can lead to a variety of issues, including backups in the septic tank itself or in the plumbing connected to the system. When the ground cannot accept more water due to saturation, effluent can surface, creating potentially harmful conditions both for the environment and for health.

In contrast, the other options do not accurately reflect the effects of heavy rainfall on septic systems. For example, heavy rainfall does not enhance treatment efficiency, as the system requires adequate soil absorption to function properly. Moreover, while it might seem intuitive that heavier rainfall would not affect the drain field, the reality is that saturated conditions can overwhelm it. Lastly, increased evaporation rates are not typically associated with heavy rainfall, since the presence of excess water would actually suppress evaporation rather than enhance it.