I have lost balls that I hit into puddles in the middle of the fairway on my wet course, and Rule 25.1c can help out: http://golf.about.com/cs/rulesofgolf/a/rule25.htm Partial quote: 25-1. Abnormal Ground Conditions c. Ball in Abnormal Ground Condition Not Found It is a question of fact whether a ball that has not been found after having been struck toward an abnormal ground condition is in such a condition. In order to apply this Rule, it must be known or virtually certain that the ball is in the abnormal ground condition. In the absence of such knowledge or certainty, the player must proceed under Rule 27-1. If it is known or virtually certain that a ball that has not been found is in an abnormal ground condition, the player may take relief under this Rule. If he elects to do so, the spot where the ball last crossed the outermost limits of the abnormal ground condition must be determined and, for the purpose of applying this Rule, the ball is deemed to lie at this spot and the player must proceed as follows: (i) Through the Green: If the ball last crossed the outermost limits of the abnormal ground condition at a spot through the green, the player may substitute another ball without penalty and take relief as prescribed in Rule 25-1b(i). You need to know with virtual certainty what happened to the ball to apply it. To me that means seeing the ball go in and not come out with my own eyes.