It's from episode 58, "Everything about the night at the Dougenkyo Part II".

Kagome-chan got captured by Toukajin (

figures

) and he put her in bath water with heads in it to clean her. InuYasha-sama finally gets freed and rushes to save Kagome-chan. When she sees InuYasha-sama rush into the room, she gets all happy that he's still alive and jumps out of the water without realizing. Well... I think you can guess what happened next!