Thousand Point Gorilla in the Room!
One Rule trumps all of the others; Rule 26 the water hazard Rule. What do I mean by that?
At times, there may be conflicts between Rules or there may be two Rules applying to the same situation. The Rules of Golf or the Decisions on the Rules will give us guidance as to which Rule overrides the other.
Decision 26/1.5 tells us that when a ball is touching a line defining the margin of a water hazard but also touches another part of the course (a bunker or through the green), the ball is considered to be lying in the water hazard. The Gorilla overrides.
When a ball is lying in a water hazard or a lateral water hazard, and the player has interference from either an abnormal ground condition (casual water) or an immovable obstruction (a sprinkler head), the player is prohibited from free relief from either of the conditions. Rather, the player must either play the ball as it lies or proceed under the water hazard Rule. The Gorilla overrides.
If your ball is lost in an abnormal ground condition or an immovable obstruction, you may substitute a ball without penalty using the spot where the ball last crossed the outermost limits of the condition as a reference point. Except when that point is in a water hazard; you must proceed under the water hazard Rule. The Gorilla overrides.
Whenever your ball lies in a water hazard, except an Environmentally Sensitive Area (ESA) defined as a water hazard or lateral water hazard, you must either play the ball as it lies if you can or proceed under the water hazard Rule.
Why? Because the Gorilla overrides!
Remember, use the index or the table of contents to find the correct Rule that applies to the situation and follow the Rules of Golf to help yourself to enjoy the game of golf.