Definitions
A hazard is any bunker or water hazard.
A bunker is a hazard consisting of a prepared area of ground, often a hollow, from which turf or soil has been removed and replaced with sand or the like. Grass-covered ground bordering or within a bunker is not part of the bunker. The margin of a bunker extends vertically downwards, but not upwards. A ball is in a bunker when it lies in or any part of it touches the bunker.
A water hazard is any sea, lake, pond, river, ditch, surface drainage ditch or other open water course (whether or not containing water) and anything of a similar nature.
All ground or water within the margin of a water hazard is part of the water hazard. The margin of a water hazard extends vertically upwards and downwards. Stakes and lines defining the margins of water hazards are in the hazards. Such stakes are obstructions. A ball is in a water hazard when it lies in or any part of it touches the water hazard.
Note 1: Water hazards (other than lateral water hazards) should be defined by yellow stakes or lines.
Note 2: The Committee may make a Local Rule prohibiting play from an environmentally-sensitive area which has been defined as a water hazard.
12-1. Searching for Ball; Seeing Ball
In searching for his ball anywhere on the course, the player may touch or bend long grass, rushes, bushes, whins, heather or the like, but only to the extent necessary to find and identify it, provided that this does not improve the lie of the ball, the area of his intended swing or his line of play.
A player is not necessarily entitled to see his ball when playing a stroke.
In a hazard, if a ball is believed to be covered by loose impediments or sand, the player may remove by probing, raking or other means as much thereof as will enable him to see a part of the ball. If an excess is removed, no penalty is incurred and the ball shall be re-covered so that only a part of the ball is visible. If the ball is moved in such removal, no penalty is incurred; the ball shall be replaced and, if necessary, re-covered. As to removal of loose impediments outside a hazard, see Rule 23.
If a ball lying in an abnormal ground condition is accidentally moved during search, no penalty is incurred; the ball shall be replaced, unless the player elects to proceed under Rule 25-1b. If the player replaces the ball, he may still proceed under Rule 25-1b if applicable.
If a ball is believed to be lying in water in a water hazard, the player may probe for it with a club or otherwise. If the ball is moved in so doing, no penalty is incurred; the ball shall be replaced, unless the player elects to proceed under Rule 26-1.