Is a player allowed to move a water hazard stake before playing a shot?

Rule 24-1: Movable Obstruction

Answer:  Under the definitions on page 17 of the USGA Rule Book it states that; Stakes used to define the margin of or identify a water hazard are obstructions.  Therefore, a stake may be removed.  If the ball moves it must be replaced and there in no penalty, provided that the movement of the ball is directly attributable to the removal of the obstruction.

Good Luck, and play well!