Which of the following is NOT a condition that can make a site unsuitable for a septic system?

In evaluating the conditions that can make a site unsuitable for a septic system, it's important to consider the implications of each factor. Rocky terrain, while challenging for installation, does not inherently make a site unsuitable for a septic system if proper measures can be taken, such as adequate design and installation techniques.

In contrast, the presence of groundwater, ledge, and impervious soil can severely hinder the effectiveness of a septic system. Groundwater presence can lead to system failure due to saturated conditions that impede the natural filtration and absorption process required for wastewater treatment. Ledge can restrict excavation depth and limit the space available for required leach fields. Impervious soils prevent wastewater from percolating through the soil, leading to surface runoff and pollution of surrounding areas. Therefore, rocky terrain is not categorized in the same critical manner as the other factors when considering site suitability for septic systems.