Water is part of even "clean" fuel fresh from the distributor.
The chance exists that the marina might change their filters often enough does exist.
Good luck ,the commercial fuel docks do a better job than marinas.
A Baja filter should catch heavy water coming in with the fuel , but is a PIA as it slows down the fueling.
The only real good solution to water in the fuel is a sump that can be pumped easily.