737 MAX Flight Crew Operations Manual
Airplane General, Emergency
Equipment, Doors, Windows -
Controls and Indicators
1.30.20
MN-FLT-OH-201
4
Water Supply Selector Valve
Each lavatory has a Water Supply Selector Valve. The Water Supply Selector
Valve has four positions, and is located in the cabinet below the sink.
SUPPLY ON – Normal operating position. When the water system is
depressurized, all lavatories except “A” will drain. In this lavatory, the drain valve
must be opened to drain the lavatory
FAUCET ONLY – In this position, water is supplied to the faucet, but not to the
toilet
TOILET ONLY – In this position, water is supplied to the toilet, but not to the
faucet
OFF – No water is supplied to the lavatory.
5
Drain Valve Handle (red)
Located in the forward lavatory only.
March 1, 2021