Cat Litter Box Problems: Why Your Cat Isn't Using It (And How to Fix It)

A cat who stops using their litter box is one of the most frustrating problems a cat owner faces — and one of the most common reasons cats are surrendered to shelters. But in most cases, the problem has a clear cause and a fixable solution.

This guide covers every reason a cat might avoid the litter box and what you can do about each one.

Rule Out Medical Problems First

Before you try any behavioural solutions, take your cat to the vet. A cat who suddenly starts urinating or defecating outside the litter box may be doing so because it hurts to use the box — and they've started associating the box with pain.

Common medical causes include:

• Urinary tract infection (UTI)
• Kidney disease
• Diabetes (causes increased urination)
• Arthritis (makes getting in and out of high-sided boxes painful)
• Hyperthyroidism
• Inflammatory bowel disease

If your vet gives your cat a clean bill of health, then you're dealing with a behavioural issue and can work through the checklist below.

The Most Common Litter Box Mistakes

1. Not Enough Boxes

The rule is one box per cat, plus one. So two cats need three boxes, three cats need four. Cats are territorial and won't always share a box comfortably. If you only have one box for two cats, one cat is probably avoiding it.

2. The Box Is Too Small

Your cat should be able to turn around comfortably inside the box. The general recommendation is that the box should be 1.5 times the length of your cat from nose to tail. Most commercially available boxes are too small, especially for large breeds or big males.

3. The Box Isn't Cleaned Often Enough

Cats are fastidiously clean. Most cats won't use a dirty box. Scoop at least once a day, ideally twice. Completely empty and wash the box every 1–2 weeks.

If you're struggling to stay on top of cleaning, a self-cleaning litter box can help — though some cats are initially wary of the automated movement.

4. The Wrong Litter

Most cats prefer fine, unscented, clumping clay litter. Scented litters mask the smell for humans but can be overwhelming for cats, whose sense of smell is 14 times more sensitive than ours. Heavily perfumed litters are one of the most common reasons cats refuse to use a box.

If you've recently changed litter brands, that could be the trigger. Go back to what was working, then if you want to switch, do it gradually by mixing the new litter in over 2–3 weeks.

5. The Location Is Wrong

Cats won't use a box that's in a high-traffic area, next to their food or water, or in a place that makes them feel trapped (no escape route, loud washing machine nearby). The box should be in a quiet, private, accessible location — not a basement they only visit occasionally.

If you've moved the box recently, move it back. Changes in box location are a common trigger.

6. Covered vs Uncovered

Some cats prefer covered boxes because they feel more private and protected; others hate them because they trap odours inside. If you're using a covered box, try removing the lid and see if behaviour improves. If you're using an open box, try adding a lid.

Why Is My Cat Going in the Same Spot Outside the Box?

If your cat repeatedly goes in the same spot outside the box, that spot has now been marked with their scent and will continue to attract them. Clean it thoroughly with an enzymatic cleaner (not bleach or ammonia, which smell similar to urine and can make the problem worse). Enzymatic cleaners break down the odour molecules rather than just masking them.

After cleaning, try placing a second litter box over that spot for a week, then gradually move it toward the correct location.

Litter Box Aversion vs Substrate Preference

Sometimes cats aren't avoiding the box itself — they've developed a preference for a different surface.

• Substrate preference: your cat likes the feel of carpet, soil, or smooth surfaces better than litter. Solution: add a box with a different texture of litter, or try a box without litter (just a smooth surface) to identify what they prefer.
• Location preference: your cat has decided they prefer to go in a corner of the bedroom or behind the sofa. Solution: put a litter box there temporarily, then gradually move it.

Stress and Multi-Cat Households

In multi-cat homes, resource guarding is common. One cat may block another from reaching the litter box (sometimes without an obvious confrontation — just a look is enough). Signs this is happening: one cat seems to avoid the box entirely, the timing of box avoidance correlates with the arrival of a new cat.

Solutions: more boxes, boxes in multiple locations, boxes with multiple entrance/exit points so a cat can't be cornered.

When to Call a Behaviourist

If you've worked through the checklist, ruled out medical issues, and your cat still isn't using the box consistently, a feline behaviourist can observe the dynamics in your home and identify something you might have missed. This is especially worth doing if the problem involves marking (spraying on vertical surfaces) rather than inappropriate elimination, as marking has different solutions.