If it is a commercially available wetsone, and not a natural wetstone it will likely soften the stone more than necessary, causing excess wear.. I soak mine maybe 15 minutes before use, rinse after use and keep them dry.
There is a difference between the types of stones used for whetting an edge. The actual name for stones is whet stones. I'm going to link to a Wikipedia article that speaks the variations between stones.
The basic synopsis: A water stone is something relatively new to the west, but the idea is still similar to the traditional Arkansas stone used in the US. An Arkansas stone can be used with either water or oil, but once it goes one way or the other, it needs to stay that way. A Japanese (or other) water stone, cannot use oil without ruining it. Here'e the Wikipedia link.