18.10 How does water get into a tank and why is it a problem?

Water enters a fuel tank from either (a) water from off-site fuel storage systems and delivery trucks, that are inadvertently introduced in to the tank, (b) water from condensation of air drawn into the tank as the fuel level is lowered.

Any water introduced into the tank will settle to the bottom of the tank. The fuel water interface at this point is a condition that promotes biological growth. This growth can be problematic especially because it can accelerate. Organic material from the fuel tank will very quickly plug the inlet filters at the engine.