Cats who stop using the litterbox are often experiencing pain. It could be upon urination, caused by a bladder infection or urinary crystals/stones. If it hurts to urinate, your cat may associate the pain with the litter box and avoid it. Cats with bladder infections frequently switch to using the bathtub or a sink to eliminate, for reasons that are unclear. It could also be due to constipation or diarrhea that the cat may also associate with the litterbox. In all these cases, it’s important to find the medical cause of your cat’s problem and treat it.
A cat who has vision problems or arthritis may need the box moved to avoid having to use the stairs to reach it since they can be difficult to navigate to with eye and/or joint problems. Switching to a litterbox with an easier “step in” can help a cat with arthritic hips. Providing a nightlight may help your older cat, especially if your litterbox is tucked away in a closet or cubbyhole (senior cats usually don’t see in the dark as well as younger ones).
“Medical reasons are certainly high on the list of reasons for avoiding litterboxes, but dirty litterboxes in a single cat household and social tensions in multi-cat households are frequent reasons for cats avoiding the litterbox,” says Pamela Perry, DVM, PhD, behavior resident at Cornell University Hospital for Animals.
Sometimes a dominant cat will stake out a litterbox as “her” turf. She may hide nearby and rush out at any other cat trying to eliminate in the box. This could prevent a newly adopted cat or kitten from using the litterbox at all. For this reason, behaviorists recommend at least one litterbox per cat plus one additional one. That way, cats can vary which box they use and, if necessary, avoid the one with the stalker.
Dogs will sometimes take advantage of a cat in the litterbox and harass their feline housemate. Dogs should be blocked off from litterboxes anyway to avoid the consumption of feline stool and litter (especially clumping litter).
From your cat’s point of view, any change might justify avoiding the litterbox. Scented litters may be overwhelming. Changing texture, from clumping to regular to pelleted, may not go over well. Even changing brands may put your cat off.
Most cats want the same litter, the same location, the same litterbox style, and the same schedule for cleaning. If you need to make changes, do so in increments. For example, if you need or want to move the location, move the box a few inches at a time. If you need to change litters, do it like you would introduce a diet change—25% new with 75% old for a few days, then 50/50, then 75/25, then the totally new option.
Litter that is too deep or shallow can upset some cats. Consistency is important. Feces should be removed daily, and periodic thorough cleanings help, totally emptying and scrubbing (or replacing) the litterbox and putting in all new, clean litter.
While cleanliness can be easy to fix, behavior problems and illnesses may take longer. Be patient. Behavior problems can vary from acute and minor, such as a longhair cat who panics when she gets poop caught on her fur, to cats who have had a serious scare at or near the litterbox. Multi-cat and multi-pet problems can cause litterbox avoidance.
It’s important to react promptly when your cat stops using the litterbox. It could be far more than concern over a mess. Litterbox avoidance can well be a call to you that your cat doesn’t feel well, is unhappy, or is being bullied by other family members. It pays to do some detective work and get to the bottom of the problem.