Uhh, a water ration is 1 G/day, or both an American GI's 1 qt canteens plus the 2 quart canteen on their ALICE pack. However, 1 ENC ≈ 3 kg, so at half an ENC, a water ration is defined as ~1.5 L. Not really enough for a human for a day, but maybe there are other sources of water in food rations and ...