The weight of a liter of water is equal to its volume multiplied by its density. The density of water is approximately 1 kilogram per liter (kg/L) at standard temperature and pressure (STP), which is 0°C (32°F) and 1 atmosphere of pressure.

Therefore, the weight of a liter of water is approximately 1 kilogram, or equivalently, 1000 grams.

In imperial units, the weight of a liter of water is approximately 2.20462 pounds (lbs).