fuel tanks and water

[OverTime]

While I was refueling the other day I started to wonder what the main causes of water in your fuel tank could be. Obviously, bad fuel from the vendor is one, but I also noticed that the fuel tank vent might allow water ingress during heavy seas or when washing down the boat etc. I wonder how likely this is? Any thoughts?

 

[Submariner]

I've been in bad seas. Never got any water in my fuel tank.

 

[bob daily]

The number one reason is condensation!

 

[OverTime]

The number one reason is condensation!

Always a good idea to keep the tank as full as possible