Litter Box 101: How Many Boxes, Where to Put Them and Why Cats Avoid Them

Litter box problems are among the most common reasons cat owners call their vet, and among the most frustrating. The good news is that most issues come down to a handful of fixable factors: the number of boxes, where they're placed, the litter and how clean they're kept. Sometimes, though, avoiding the box signals a medical problem.

How many litter boxes do you need?

The widely recommended rule is one box per cat, plus one extra. One cat needs two boxes, and two cats need three. Multiple boxes reduce competition and give a cat options if one box is dirty or another cat is guarding it.

Where to put litter boxes

• Quiet, low-traffic spots, away from noisy appliances like washing machines.
• Away from food and water bowls. Cats don't like to eliminate near where they eat.
• On every level of a multi-story home, especially for older cats.
• In separate locations, not side by side, so one cat can't block access to all of them.
• Somewhere with an escape route, so a cat doesn't feel trapped.

Choosing the right box and litter

Bigger is better. A good guideline is a box about 1.5 times the length of your cat. Many cats prefer uncovered boxes, which don't trap odors inside. Senior cats or cats with arthritis need a low entry.

Many cats prefer unscented, fine-grained clumping litter. Strong fragrances that smell pleasant to people can be off-putting to a cat's sensitive nose. Keep about 2 to 3 inches of litter in the box, and if you change litter types, transition gradually by mixing the new with the old.

Cleaning schedule

• Scoop at least once a day. Twice is better in multi-cat homes.
• Top up litter as needed to maintain depth.
• Empty and wash the box with mild, unscented soap and warm water regularly, about every 2 to 4 weeks for clumping litter. Avoid harsh-smelling cleaners like ammonia or bleach residue.

Why cats stop using the litter box

• The box is dirty or there aren't enough boxes.
• Changes in litter, box type or location.
• Stress: a new pet, a new baby, moving, visitors or conflict with another cat.
• Negative association: a scary event, such as a loud noise or being medicated, while in the box.
• Medical problems: urinary tract issues, bladder inflammation, kidney disease, diabetes, constipation or arthritis can all cause litter box avoidance.

When it's an emergency

If your cat, especially a male cat, is straining in the litter box and producing little or no urine, crying while trying to urinate, or repeatedly visiting the box, see a veterinarian immediately. A urinary blockage is a life-threatening emergency that requires urgent treatment.

The bottom line

Provide enough clean, well-placed boxes with litter your cat likes, and most problems disappear. If a cat suddenly changes its habits, rule out a medical cause with your veterinarian before assuming it's behavioral.