A cat not using the litter box is the number one behavior complaint cat owners bring to vets and shelters, and it is also one of the most fixable. Cats are clean animals by nature. When one stops using the box, they are telling you something, and it is almost never spite. It is usually one of five things.
1. The box is not clean enough for their standards
Their standards are higher than yours. Scoop at least once a day, dump and wash the box monthly, and skip the scented litters. A cat’s nose is roughly fourteen times stronger than a human’s, and a perfume-scented box can smell like a chemical factory to them. Most litter box problems end at the scoop.
2. Not enough boxes, or the wrong kind
The rule is one box per cat, plus one. In a two-cat house that means three. Covered boxes are popular with owners and often hated by cats: they trap odor and create an ambush point another pet can guard. A big open box with unscented clumping litter wins most cage matches.
3. The location is wrong
Cats want a quiet spot away from the washing machine and the dog’s food bowl, but not so hidden they feel cornered. If the box moved recently, or a new pet, baby, or houseguest changed the routine, stress alone can do it. Put a box back in the old location if you can.
4. It hurts when they go
This is the one you never wait out. Straining, frequent trips, crying in the box, or blood in the urine means a vet visit now, especially for male cats, where a blockage is an emergency. A cat who associates the box with pain will avoid it, which is why a medical problem can look exactly like a behavior one.
5. The accident scene still smells like an accident
Clean past mistakes with an enzyme cleaner, never ammonia. Ammonia smells like urine to a cat, and you are basically re-marking the spot for them.
Related reading: bringing home your first cat? Start with adopting a cat for the first time.