Where are the lavatory manual water shut-off valves located on the ERJ 175?

The correct choice indicates that the lavatory manual water shut-off valves are located in both the forward (FWD) and aft (AFT) lavatories of the ERJ 175. This is critical for maintenance and emergency procedures, allowing flight crews to manage lavatory water supply individually in both areas of the aircraft. Having shut-off valves in both lavatories enhances operational safety by enabling specific control over water flow in case of a leak or malfunction, providing the crew with better tools to handle in-flight issues efficiently.

Ensuring access to shut-off valves in multiple locations is a standard safety feature in aircraft design, allowing for rapid response to potential plumbing problems without impacting the entire lavatory system. Hence, the availability of these valves in both the FWD and AFT lavatories supports crew management of aircraft systems.