If I were inclined to house rule this, which I'm not sure I am, I might try:
Existing Rule:  
* Athletics Skill:  Reduce Falling Damage: Free action if you fall or a move action if you jump down.  Damage Reduced: Make an Acrobatics check, and reduce the amount of falling damage you take by one-half your check result (round down).
House Rule:
* Reduce the amount of falling damage by your check result if you fall into water.
Cheers,
Roger