How much water does a boat crew use per day?
We plan on 25 litres per person per day for a cruising crew, and between 15 and 50 depending on the kind of boat and how it is used. That is a planning figure, not a measurement — the only number that matters is your own, and it is easy to get.
Consumption is behaviour, not specification. The same boat can run at 15 litres a head with a saltwater deck wash and quick showers, or 50 with guests, laundry and a swim platform rinse after every dip. Charter operators plan high because guests do not ration, and liveaboards drift upward once making water stops feeling like an event.
Measure it before you buy: note your tank level over a week of normal use and divide. A figure you have measured beats every table on the internet, including ours, and it is the input the sizing calculator actually wants.
Where this is worked through
Other quick answers
Where these numbers come from. Every figure on this page is computed at build time from the comparison table — rated output and rated draw as the manufacturer publishes them, with watt-hours per litre derived as one divided by the other. Nothing is typed in by hand, so nothing here can drift from the table. Where a figure is an assumption rather than a specification it is labelled as one. Methodology · the table.