Water leaking

[61Hawks]

It may seem like a stupid question but on the new 300c when I fill with fresh water it doesn't pour in like on our older unit but screws on like a hose does. Now when it was full or I think it was water doesn't pour out the vents line. So on our trip when we stopped on one side then later on the other side water came out the bottom from what appear to be drains. One is in front of the passenger front tire and the other is one of two in the Grey/black compartment. Are these overflow drains or vents or what? It is fresh water. Thanks