Definition
Water that is safe for human drinking, meeting health and sanitation standards for purity and freedom from harmful contaminants. On aircraft, potable water is carried in a dedicated tank and plumbing system separate from any non-drinking water supply, and is used for galley service, lavatory sinks, and crew/passenger consumption.
Plain English
Drinking water — clean enough to drink without getting sick. On an aircraft, it is the water supplied for sinks, coffee, and drinks, kept in its own tank apart from any other water on board.
Context Anchor
Seen in aircraft servicing, cabin service, lavatory and galley procedures, and maintenance records for aircraft water systems.
Derivation
From the Latin potabilis, meaning 'drinkable,' from potare, 'to drink.' The same root gives us 'potion.' Knowing the root makes the meaning obvious: potable water is simply water you can drink.
Why Pilots Care
Unsafe water can cause illness among crew or passengers that may compromise flight safety or require diversion.
Intuition Check
Potable does not mean portable. Potable water is water safe to drink; portable water would simply mean water that can be carried.
Example Sentence 1
The ground crew topped off the potable water tank before the long-haul flight.
Example Sentence 2
Cabin crew confirmed the potable water was serviced before boarding passengers.