How many total water shut off valves are available in the lavatory?

The total number of water shut-off valves available in the lavatory is typically two. This configuration allows for both the hot and cold water lines to be controlled independently, providing maintenance personnel with the ability to isolate the water supply in case of a leak or when performing repairs without affecting other systems on the aircraft. Having two distinct valves enhances safety and operational flexibility, which is essential in an aircraft environment where quick responses to maintenance issues are critical. This design standard is common across many aircraft types in order to streamline maintenance procedures and ensure that water supply can be effectively managed.