How often should a manhole be installed in a sewage system?

A manhole is an essential component of a sewage system, serving as access points for maintenance, inspection, and cleaning of the sewer lines. The correct answer emphasizes that a manhole should be installed each time a sewer line changes direction. This practice is crucial because changes in direction can accumulate debris or create blockages without the ability to inspect or clear them. By having a manhole at these critical points, personnel can access the system to ensure it functions efficiently and is free of obstructions.

Manholes also provide a means to inspect and monitor the integrity of the sewer infrastructure, preventing potential issues from becoming severe or leading to major malfunctions. Proper spacing of manholes, particularly at directional changes, enhances the operational efficiency of the sewage system and assists in maintaining public health and environmental standards.

Other choices suggest infrequent installation of manholes, which would be impractical for effective maintenance and oversight of the sewer system. Regular spacing and installation based on line changes ensure ongoing functionality and safety.