A cat suddenly peeing outside the litter box can happen for several reasons, primarily related to medical issues, stress, or litter box conditions.

Medical Issues

Common medical problems causing this behavior include urinary tract infections (UTI), bladder stones, feline idiopathic cystitis (FIC), kidney disease, diabetes, arthritis, or other causes of pain and discomfort. These conditions can make urination painful or difficult, leading cats to associate the litter box with pain or to have incontinence, causing them to urinate outside the box. It is important to have a vet check the cat for these issues since some require prompt treatment.

Stress and Environmental Changes

Cats are sensitive to changes in their environment. New pets, babies, visitors, home renovations, moving to a new home, or changes in routine can stress a cat and cause inappropriate urination. Stress can also make cats forget litter box habits or feel unsafe using their box. Ensuring a stable environment may help reduce this behavior.

Litter Box Factors

Cats might avoid the litter box if it’s dirty, in a noisy or high-traffic area, or if the type or location of litter box changes. Older cats with arthritis may struggle to access boxes with high sides. Cats prefer clean, quiet, and private places for elimination.

If a cat suddenly starts peeing outside the litter box, a veterinary checkup is the first step to rule out health problems. Resolving medical issues, minimizing stress, and optimizing litter box conditions usually help correct the behavior.