1000 liters equal to what weight?

At standard temperature, 1 liter of pure water has 1 kg mass.

1,000 liters = 1,000 kg.

On earth, 1,000 kg weighs about 9,800 newtons (2,205 pounds).
1,000 liters of water weighs approximately 2,205.8362 pounds or 1,000.550 kg