Will Berryman B-12 remove water from my gas tank?

 

no, buy some Heet.

 

Keep the tank at least half-full in cold weather (or a quarter at minimum), avoid cheap cut-rate gas brands, and don't fill up at the gas station until at least 5-10 minutes after the tanker-truck has stopped pumping gas into the underground tanks, and you will minimize your chances of getting water in the tank to start with.

For getting rid of existing water in the system, most alcohol-based products will probably do the job. BG-44K produces a number of excellent fuel-system cleaners and treatments, but the generally aren't available in stores.....you usually have to order them or get them from repair shops.