All defined terms are in italics and are listed alphabetically in the Definitions section - see pages 2235.
It is a question of fact whether a ball that has not been found after having been struck toward a water hazard is in the hazard. In the absence of knowledge or virtual certainty that a ball struck toward a water hazard, but not found, is in the hazard, the player must proceed under Rule 27-1.
If a ball is found in a water hazard or if it is known or virtually certain that a ball that has not been found is in the water hazard (whether the ball lies in water or not), the player may under penalty of one stroke:
a.
Proceed under the stroke and distance provision of Rule 27-1 by playing a ball as nearly as possible at the spot from which the original ball was last played (see Rule 20-5); or
b.
Drop a ball behind the water hazard, keeping the point at which the original ball last crossed the margin of the water hazard directly between the hole and the spot on which the ball is dropped, with no limit to how far behind the water hazard the ball may be dropped; or
c.
As additional options available only if the ball last crossed the margin of a lateral water hazard, drop a ball outside the water hazard within two club-lengths of and not nearer the hole than (i) the point where the original ball last crossed the margin of the water hazard or (ii) a point on the opposite margin of the water hazard equidistant from the hole.
When proceeding under this Rule, the player may lift and clean his ball or substitute a ball.
(Prohibited actions when ball is in a hazard - see Rule 13-4)
(Ball moving in water in a water hazard - see Rule 14-6)
If a ball played from within a water hazard comes to rest in the same or another water hazard after the stroke, the player may:
under penalty of one stroke, play a ball as nearly as possible at the spot from which the last stroke from outside a water hazard was made (see Rule 20-5); or
proceed under Rule 26-1a, 26-1b or, if applicable, Rule 26-1c, incurring the penalty of one stroke under that Rule. For purposes of applying Rule 26-1b or 26-1c, the reference point is the point where the original ball last crossed the margin of the hazard in which it lies.
Note: If the player proceeds under Rule 26-1a by dropping a ball in the hazard as near as possible to the spot from which the original ball was last played, but elects not to play the dropped ball, he may then proceed under Clause (i) above, Rule 26-1b or, if applicable, Rule 26-1c. If he does so, he incurs a total of two penalty strokes: the penalty of one stroke for proceeding under Rule 26-1a, and an additional penalty of one stroke for then proceeding under Clause (i) above, Rule 26-1b or Rule 26-1c.
If a ball played from within a water hazard is lost or deemed unplayable outside the hazard or is out of bounds, the player may, after taking a penalty of one stroke under Rule 27-1 or 28a, play a ball as nearly as possible at the spot in the hazard from which the original ball was last played (see Rule 20-5).
If the player elects not to play a ball from that spot, he may:
add an additional penalty of one stroke (making a total of two penalty strokes) and play a ball as nearly as possible at the spot from which the last stroke from outside a water hazard was made (see Rule 20-5); or
proceed under Rule 26-1b or, if applicable, Rule 26-1c, adding the additional penalty of one stroke prescribed by the Rule (making a total of two penalty strokes) and using as the reference point the point where the original ball last crossed the margin of the hazard before it came to rest in the hazard.
Note 1: When proceeding under Rule 26-2b, the player is not required to drop a ball under Rule 27-1 or 28a. If he does drop a ball, he is not required to play it. He may alternatively proceed under Clause (i) or (ii) above. If he does so, he incurs a total of two penalty strokes: the penalty of one stroke under Rule 27-1 or 28a, and an additional penalty of one stroke for then proceeding under Clause (i) or (ii) above.
Note 2: If a ball played from within a water hazard is deemed unplayable outside the hazard, nothing in Rule 26-2b precludes the player from proceeding under Rule 28b or c.
Match play - Loss of hole; Stroke play - Two strokes.