What is a key outcome of improper septic system design?

A key outcome of improper septic system design is potential environmental contamination. When a septic system is not designed or installed correctly, it can fail to effectively treat wastewater. This failure can lead to the leakage of untreated or partially treated sewage into the surrounding soil, groundwater, or surface water. Contaminants such as pathogens, nutrients, and chemicals can then spread into the environment, posing significant risks to public health and ecosystems.

For instance, groundwater contamination can pollute drinking water supplies, leading to serious health concerns for individuals relying on that water. Additionally, nutrient overloads from improperly functioning systems can contribute to problems like algal blooms in nearby bodies of water, disrupting aquatic ecosystems and affecting wildlife.

In contrast, options like increased energy efficiency, improved soil fertility, and enhanced residential value do not relate to the effects of improper septic system design. A failing system typically contributes to higher energy costs due to added maintenance or repairs, does not enhance soil fertility (as contamination can actually harm soil health), and can decrease, not enhance, residential property value due to the negative implications of a malfunctioning septic system.