Water in the Gas Tank

[kb79]

I just checked our fuel filter and found water for the first time since we've owned the boat. My first thought was that the deck fill was leaking, but I just came up with another theory that I wanted to run by you guys:

We've been motoring more than usual lately, and for the first time maybe ever (since owning the boat), we've been motoring in rough(er) seas. I thought maybe the water's been in the gas tank the whole time and has just been sucked into the filter due to the added turbulence in the tank while the engine's on? Does that sound possible?

If not, what are other ways water might have gotten in there outside of a leaky deck fill or just bad gas?

Thanks for the help.

[Philsboat]

Check the "O" ring seal on the filler cap.It should be flexible with no cracks.

[Laidback]

Gasoline or Diesel Tank ??

Sounds like condensation - moisture becomes water - heavier than diesel, sits on the bottom until stirred up; the fuel pick up tube is usually 1/2 <> 1" off the bottom the tank.

[GordMay]

The more nearly full you keep your fuel tank, the less moist air it can contain, and the less cool surface area (inside tank) upon which that moisture may condense (if the tank is cooler than the air.).

Then there’s David Pascoe’s (slightly mistaken) belief that Condensation in Fuel Tanks is just a Myth.
➥ The Myth of Condensation in Fuel Tanks by David Pascoe: Boat Maintenance, Repairs and Troubleshooting