Cat Behavior Knowledge

Is Your Cat Suddenly Not Using the Litter Box? Explore Four Common  Causes!

In today's busy world, many people choose to adopt cats for convenience. Cats are independent and can use litter boxes, making them a low-maintenance pet that doesn’t require daily walks.

However, one issue that often drives cat owners crazy is when their cats suddenly start going outside the litter box.

Almost every cat owner has experienced this problem at some point. Some cats use the litter box when they’re young, but as they grow older, they suddenly stop, leaving their owners wondering: “Why did my cat used to use the litter box, but now suddenly doesn’t?”

Today, I’ll outline four common reasons why your cat might suddenly stop using the litter box. If you’re dealing with the same problem, following these tips can help you understand and resolve the issue.

Common Reason 1: They’re Unwell

All cats are naturally inclined to use litter boxes—it's part of their instinct and preference. If your cat used to use the litter box and suddenly stops, regardless of age, the first thing to rule out is any health problems. Various physical conditions can make a cat unable or unwilling to use the litter box, such as acute cystitis, spontaneous cystitis, urethral obstruction, acute or chronic kidney disease, gastrointestinal issues, constipation, arthritis, or joint pain. The simplest solution is to take your cat to the vet for a check-up.

Common Reason 2: They’ve Grown or Gained Weight

Just like parents upgrade clothing sizes as their children grow, cat owners should do the same with litter boxes. Sometimes, people start with a small litter box for a kitten but forget to replace it as the cat grows. Or, as they watch their cat gain weight, they don’t think about enlarging the litter box. These situations can make a cat reluctant to use a cramped box, or their urine or feces may end up outside the box because they’re too big for it.

A common question I get is, “How big should a litter box be?” It’s simple: the litter box should be large enough for your cat to comfortably turn around without touching the sides. Also, make sure the box is placed in a way that allows the cat to move around easily.

Common Reason 3: They’ve Had Enough!

What type of litter are you using? One of the most important factors for cats when choosing a litter box is the type of litter inside. Many cats who suddenly stop using the box do so because the litter is not their preferred type. I always remind owners that most cats prefer unscented, fine-grained clumping clay litter. If your cat has been using a type of litter they don’t like for a long time, they might have just reached their breaking point.

Research in 2017 found that cats express 39 different emotions while using a litter box, and some will suppress their dislike and continue using the box, but may hold their urine longer or reduce the frequency of use. Another 2018 study showed that cats prefer finer, softer litter types, with clumping clay litter being the most popular.

In my experience, almost all cases of inappropriate urination are caused by using the wrong type of litter. Common disliked litters include tofu, pine, corn, or crystal litter. If you’ve been using one of these, your cat might have finally had enough!

Signs that your cat dislikes the litter include leaving without covering waste, balancing on the edges of the box, or scratching the floor or sides of the box after using it. These behaviors are a clear message: they’re fed up!

Common Reason 4: Stress

In multi-cat households, cats may avoid the litter box out of fear of conflict, choosing instead to go in safer, more private areas like the sofa, closet, bathtub, or bed. If your cat feels threatened by strangers or unfamiliar objects near the litter box, they might avoid it altogether. Other sources of stress include thunderstorms, fireworks, or loud celebrations, all of which can make a cat too scared to use the litter box.

Once you understand these stressors, if your cat suddenly starts going outside the litter box, don’t think they’re doing it on purpose. Instead, help them feel safe and reduce their stress.