Question: how many lbs in 1/2 gallon?
Answer: How much water equals 15 pounds? 1 gallon of water weighs approximately 8.3 pounds so 2 gallons of water would weigh approximately 16.6 pounds. If you add slightly less than 2 gallons of water to the medicine ball, you will have approximately 15 pounds of water weight (plus the weight of the medicine ball itself.)