Litter Box Problems: Why Cats Stop Using the Tray and How to Fix It

A cat that stops using its litter box is almost always telling you that something is wrong, not being naughty, and the first job is to rule out a medical cause before treating it as a behaviour problem. House soiling, the technical term is inappropriate elimination, is one of the most common reasons cats are given up, and yet most cases come down to a short list of fixable causes: a dirty tray, the wrong litter or box, a poor location, too few boxes, stress, or an underlying illness.

This sits within our cat behaviour guide; start there for the wider picture of why cats do what they do.

See a vet first: rule out a medical cause

Always rule out illness before assuming the problem is behavioural. Many cats that stop using the tray are in pain or unwell, and they cannot tell you any other way. The most important cause to exclude is feline lower urinary tract disease, which is one of the most common reasons cats are seen by a vet for urinary signs. Straining, going more often, passing only small amounts, or blood in the urine all point to a urinary problem and need a vet (see our guide to urinary problems in cats).

One sign is a true emergency: a male cat straining in the tray with little or nothing produced may have a blocked bladder, which can become fatal within a day or so. That is a go-straight-to-a-vet situation, not a wait-and-see one. Beyond the bladder, conditions such as kidney disease, diabetes, arthritis (which makes climbing into a high-sided box painful), and digestive upsets all show up as litter changes. This is why every reputable source, from Cornell to the AAFP, puts a vet check first.

Cleanliness: the most common fixable cause

The single most common practical reason a cat avoids the tray is that it is not clean enough. Cats are fastidious, and a box that smells strongly to us is overwhelming to a nose many times more sensitive. Scoop solids and clumps at least once a day, ideally twice, and do a full litter change and box wash regularly; with clumping litter most owners manage a full change every one to two weeks, sooner with more than one cat. Wash the box with unscented soap and warm water, not strong disinfectants, which can leave a smell cats dislike. I learned this the slow way: my older cat, Mabel, began leaving little protests on the bath mat, and it took me an embarrassing week to realise I had simply let her tray get one day too full.

Litter type: most cats want fine, soft, unscented

Most cats prefer a fine, soft, unscented clumping litter. This texture is closest to the loose, sandy substrate a cat would naturally choose to dig and bury in. Heavily scented litters, deodorising crystals, and floral additives are made to please owners, and a good proportion of cats find them off-putting. If you want to switch litter, do it gradually: mix the new type in with the old over about 7 days, the same slow-transition principle we use for cat food changes. Sudden swaps are a classic trigger for a cat quietly relocating its business elsewhere.

The box itself: bigger, open, lower

The box should be big, open, and easy to get into. International Cat Care suggests a tray about one and a half times the length of your cat from nose to base of tail, which is usually larger than the boxes sold as standard. Most cats prefer an uncovered tray: hoods trap odour, offer only one exit (which can feel like a trap), and stop a nervous cat seeing another pet approach. For kittens and older arthritic cats, choose at least one box with a low side so climbing in is not a struggle, the same access thinking that matters for any senior cat.

Location: quiet, safe, and not next to the food

Put boxes in quiet, low-traffic spots where a cat feels safe and is not cornered. Cats dislike toileting where they eat, so keep the tray well away from food and water bowls. Avoid noisy appliances, busy thoroughfares, and dead-end corners with only one way out; a cat startled mid-use may decide the box is no longer safe. In a multi-floor home, provide a box on each level so the tray is never a long, daunting trip away.

Number of boxes: one per cat, plus one

Follow the one-per-cat-plus-one rule. One cat needs two boxes, two cats need three, three cats need four, and so on. Just as important, spread the boxes around the home in different rooms; cats view several trays lined up in one spot as a single resource. In multi-cat homes this rule stops a confident cat guarding the only tray and leaving a timid one nowhere to go.

Stress and conflict: the hidden trigger

Stress is one of the most common drivers of house soiling once medical causes are ruled out. Cats are creatures of routine and territory, so a house move, building work, a new baby, a new pet, or even a change in your hours can unsettle them enough to stop using the tray, or to spray-mark. Tension between cats in the home is a frequent culprit, which is why introductions matter so much (see introducing two cats). Plenty of vertical space, hiding spots, predictable routines, and good indoor enrichment all lower the background stress that spills over into the litter tray. Never punish accidents: punishment adds fear, and a frightened cat soils more, not less.

A simple plan if your cat is soiling

Work through it in order. First, book a vet check to rule out illness, urgently if there is any straining. While you wait, clean soiled spots with an enzyme cleaner (not ammonia or bleach, whose smell can invite repeat marking), add boxes to hit the one-per-cat-plus-one count, switch to a large open tray with fine unscented litter, scoop twice a day, and move trays to quiet, separate locations. Address obvious stressors and give any change a couple of weeks to settle. If the problem continues once your vet has given the all-clear, ask about a referral to a qualified behaviourist.

This guide is general information, not a diagnosis. Litter box problems can have a medical cause that only an examination will find, so anything new or worrying about your own cat should be checked by your vet, who can examine your cat and knows its history.