Fill your aft fresh water tank, and pump or use sufficient from your forward tank until the puddle runs away. I suspect your problem may be more than just the fact that a puddle exists, such as a leak making internal areas wet. If that is the case then after trimming your boat to get rid of the puddle, that you find where the leak is and use some "Captain Tolleys Creeping Crack Cure" it's brilliant for sealing leaks and does exactly what it says on the container.
