One metric tonne is 1000kg, so that would be 1,000 Litres of water. You can't really compare a volume with a mass except by introducing density, water having a convenient density of 1.

- keeping to metric units
- One cubic metre of water = 1ton
- One kilograms of water =1 kilogram
- There is 1000 kg in a tonne
- Therefore 1000, litres is in a ton