What is the purpose of using a riser on a septic tank?

The purpose of using a riser on a septic tank is to provide easier access for inspections and pumping without the need for excavation. Risers extend the access point of the septic tank to ground level, which significantly simplifies the process of maintaining the system. When a riser is in place, it allows service personnel to quickly and efficiently inspect the tank and perform necessary pumping or maintenance duties without the labor-intensive task of digging up the ground. This accessibility promotes regular upkeep, which is crucial for ensuring the longevity and proper functioning of the septic system, ultimately helping to prevent costly repairs or system failures.

The other options do not accurately reflect the primary function of risers. They do not increase the capacity of the tank, prevent soil erosion, or primarily serve to enhance the visual aspects of the septic system. The primary focus of risers is functional access, making option B the correct choice.