Water barrels need to have 20-50k water, not 500.

[Dragonchampion 107]

Right now, 1 Waterskin weighs as much as 110 water jars, but water jars can hold 22000 water, where a water barrel can hold only 500. Plus, it's ridiculous that a water barrel can only hold 500, 5 uses. An average 16th century barrel held 42-50 gallons of water... and most humans drank 1 gallon of liquid a day, often as alcohol of some sort.

[Astronovalol 12]

+1