A sump pump can be installed at the base of an elevator shaft when the discharge is?

A sump pump installed at the base of an elevator shaft is permitted when the discharge is indirectly connected to the plumbing system. This type of connection allows for proper drainage of collected water while ensuring that the water does not directly flow into the sanitary or storm sewer systems without appropriate treatment. An indirect connection typically involves a sump pit or a designated area where the water can be discharged safely, preventing potential contamination of the potable water supply or other plumbing systems. This configuration is particularly important in elevator shafts to manage water accumulation effectively while adhering to plumbing codes that prioritize safety and sanitation.

While the other options suggest various forms of monitoring and protection, they do not align with the criteria established for sump pump discharge in relation to elevator shafts. Ensuring that the discharge is indirectly connected maintains compliance with local regulations and standards regarding plumbing installations.