Which is not a variable to consider when deciding on a safe distance between a well and a sewage disposal system?

The correct focus is on selecting the variables that directly influence the safety of water supply from a well in relation to potential sewage contamination. The number of individuals utilizing the well is not a factor that affects the physical distance required between a well and a sewage disposal system. While higher usage may impact the rate at which water is drawn, it does not inherently change the risk of contamination from sewage.

In contrast, well construction and sealing of the annular space are critical as they directly influence how well contaminants can be kept out of the well. The integrity of the well and proper sealing are essential to prevent any surface pollutants from reaching the groundwater.

Considering the volume and strength of polluted material is also vital since it helps in assessing the potential for contamination. Higher volumes or stronger pollutants could necessitate a greater distance to effectively reduce the risk of contamination.

Soil structure and texture also play an important role, as these factors affect how quickly and effectively contaminants move through the ground. Certain soil compositions can filter pollutants better than others, which can inform decisions about required distances for safety.

Thus, while other variables can directly affect the likelihood of contaminants reaching the well, the actual number of users does not influence the physical dynamics of contamination and is therefore not a variable that should be considered