Instructions
Fill the tub with one or two inches of water. Most cats hate water and your cat will stop trying to get into the tub If you fill it consistently.
Use a different type of litter for the litter box. Some cats have a particular preference for litter and you might need to experiment with different kinds.
Purchase a covered litter box if yours is uncovered, or an uncovered litter box if yours is covered. Your cat might prefer one over the other.
Take your cat to the vet to rule out urinary tract infections or other health issues. If the cat is having trouble urinating, he might associate the pain with his litter box and use the bathtub instead.
Move the litter box to a different location. If your cat doesn̵7;t like where it̵7;s located he will go somewhere else.
Keep the litter box clean. Since cats are clean animals, they won̵7;t want to use the litter box if you don̵7;t empty it on a regular basis.
Put litter in only one half of the box. Your cat may be going in the bathtub because he prefers hard surfaces.
Keep the bathroom door closed to give the cat the message that he should go somewhere else. After a number of failed attempts, he should stop trying to enter the bathroom,
How to Keep Cats Out of the Bathtub
Many cat owners have trouble keeping their cats out of the bathtub. A cat might enter the tub because he likes the texture or to use the bathroom. Owners need to figure out why their cat prefers using the bathtub and take steps to remedy the problem so that the cat won̵7;t form an undesirable habit.