Litter Box Setup: How Many, How Big, Where to Put It

One box per cat plus one extra, each at least 1.5 times the length of the cat's body without the tail, uncovered, filled with 5-7 cm of unscented clumping litter, and placed in a quiet corner with two ways out and no food or water nearby. Set up that way, most litter box problems never start. Set up badly, no amount of cleaning fixes them.

How many boxes

The formula is cats plus one: one cat gets two boxes, two cats get three, three cats get four. The reason is not hygiene but politics — in a multi-cat house the box is a resource that gets guarded, and a cat that is blocked from one box needs somewhere else to go that does not smell like the cat who chased it off.

The boxes should be in different rooms, not lined up in a row in the laundry. Two boxes side by side count as one socially, because the same cat can still guard both from a single spot.

Size: bigger than the box you already own

Measure your cat from nose to the base of the tail. The box should be at least 1.5 times that, which for an average adult cat means 60 cm long and 40 cm wide, and for a Maine Coon closer to 75-90 cm. Most commercial boxes are sold too small, and the "large" label on the packaging usually means large for a kitten.

An honest test: put the cat in the box. It should be able to turn around, scratch three or four times in a row, and squat without its nose touching a wall or its rear hanging over the edge. If not, the box is the problem — not the cat's aim.

The cheapest good box is a 60-80 litre plastic storage tub with a door cut into one long side, leaving a 15 cm lip at the bottom. It is deep enough that nobody kicks litter over the edge, and it costs a third of a purpose-made box.

Placement: quiet, open, and two exits

Cats want to see who is coming while they are exposed. Put the box in a low-traffic room, against a wall but not boxed into a corner with only one way out, away from the washing machine, the boiler and the front door. Not next to the food and water bowls — cats will eat next to a kill, but they will not toilet next to a meal, and a box beside the bowl is a common cause of both refusing food and going on the floor.

In a two-storey home, one box per floor. An old cat will not do stairs at 3 a.m., and a cat that has to choose between stairs and the carpet chooses the carpet.

Leave the box where it is. Moving it two metres to make room for a plant is enough to trigger accidents in a cat that was fine for years.

Litter: unscented, clumping, 5-7 cm deep

Unscented clumping litter in a fine grain is the default that most cats accept. Scented litter exists for humans, not cats — a cat's nose is roughly 14 times more sensitive than ours, and a perfumed litter is like using a toilet in a candle shop. If you want to change litter type, do it over two weeks by mixing, and keep one box on the old litter while you do.

Depth matters more than brand: 5-7 cm lets a cat bury properly. Less than 3 cm and the litter sticks to the bottom, which makes scooping miserable and the box smell.

Skip the liner. Most cats dislike the crinkle, and a cat that scratches through it creates a pee pool under the bag. Skip the deodorising powder too: it clumps into cement at the bottom and does nothing about the ammonia that forms below the surface.

The cleaning rhythm

• Twice a day: scoop solids and clumps. Morning and before bed. A box scooped twice a day is a box a cat will use.
• Weekly: top up litter to depth, wipe the rim.
• Every 2-3 weeks: empty it completely, wash with hot water and unscented dish soap, dry in the sun, refill fresh. Non-clumping litter needs a full change weekly.
• Yearly: replace the box. Plastic scratches, and scratches hold bacteria that no amount of scrubbing removes — this is the usual reason an older box starts to smell no matter what you do.

Never use bleach, ammonia or pine cleaners on the box. Ammonia smells like urine to a cat and invites marking; the residue also puts cats off the box entirely.

Kittens, seniors, and small flats

Kittens need a shallow box with a 5 cm lip they can climb over, placed close to wherever they sleep, and one on every floor they are allowed on. Under 12 weeks, put the kitten in the box after every meal, every nap and every play session — that is how the habit forms.

Seniors and arthritic cats need a box with a low entry, 10 cm or less, and no hood. A cat with sore hips will not climb a 20 cm wall twice a day.

Small flats often cannot fit two boxes. Then make one box count: the largest one that fits, scooped after every use, in the quietest spot available. If the flat has a bathroom, that is usually the best room in the house for it.

When a cat stops using the box

First rule: a cat that suddenly urinates outside the box, especially on cool smooth surfaces like a sink or bathtub, gets a vet visit before any behaviour work. Urinary blockages, cystitis and kidney disease all present this way, and a blocked male cat can die within 24-48 hours. The health section lists the signs to check.

If the vet clears the cat, then look at the setup in this order: box too small, too dirty, too close to food, hooded, or in a spot where another cat ambushes. Change one thing at a time and give it two weeks. Cats do not act out of spite; they avoid a box that fails one of the five tests above.

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