[sandcruiser]

Seems to me that if you are pulling the oil straight out of the fryer, you probably don't have to worry about water.

it is unwise to build a WVO fuel system without a water-separator anyway. What little water might be left in the oil should get caught there.

having said that, if you have space in the garage to let oil settle out for a week or two, the only downside to doing so is that you use up a little storage space. The benefits include less particulate clogging up your filters (both your wvo filter and your fuel filter(s)) and less chance of introducing water, and if you've got any tallow or other fatty solids, those should settle out as well.