The cat litter tray: correct setup and troubleshooting

The litter tray is one of the most underrated aspects of cat care. A correct setup prevents 80% of "cat pees outside" problems. This guide covers everything: size, litter, location and diagnosis when something goes wrong.

Correct size

Basic rule: the litter tray should be 1.5x the length of the adult cat. For a common domestic shorthair (4-5 kg) → litter tray of at least 50x40 cm.

Common mistakes:

• A "kitten" tray used for an adult cat (result: pee outside)
• A tray with a very small hood so the cat feels cramped inside
• Very high sides for senior cats with osteoarthritis (result: pee next to it)

For large cats (Maine Coon, Ragdoll) or several cats sharing: an IKEA storage box like the "Samla" 78x56 cm works great. More spacious = better use.

Types of litter available

• Clumping bentonite (classic) — the favourite of most cats. Clumps well, easy to clean. ~€6/10 kg. Dust: medium.
• Silica (crystals) — absorbent, lasts 2-3 weeks without changing. ~€12/5 kg. Doesn't clump. Some cats reject the texture.
• Tofu / pine / maize — biodegradable, less odour. ~€10/6 kg. Some cats eat it (careful with kittens).
• Recycled paper — recommended post-surgery (doesn't stick to wounds). Temporary only.
• Unscented ALWAYS: cats detest strong smells. Fragrances are for humans, not for cats.

The MOST important thing: once you find the litter your cat accepts well, do NOT change it. Sudden brand changes are a leading cause of "pee outside".

Location: where to place it

Location matters. A good spot:

• Quiet area, away from noise (not next to the washing machine or dishwasher)
• Easy access but not in a high-traffic hallway
• Away from their food and water (at least 1 metre, ideally another room)
• Well ventilated (not in a closed cupboard)
• Near areas the cat uses (not too far from where they sleep)

BAD places: a very cold garage, an unprotected balcony, a noisy utility room, next to the travel carrier (they associate litter tray = vet trip).

How many litter trays per cat?

Golden rule: number of cats + 1.

• 1 cat → 2 litter trays
• 2 cats → 3 litter trays
• 3 cats → 4 litter trays

Distribute them across different floors/rooms. Cats can block each other — one sits in front and the other can't use it. More litter trays = fewer territorial conflicts.

For very old cats with osteoarthritis, consider litter trays on ALL floors (at least one per floor) to avoid them having to climb stairs.

Frequency and method of cleaning

Daily: remove faeces and clumped urine balls with a scoop (ideally scoop 1-2 times/day).

Every 1-2 weeks: empty completely, wash the box with water + mild soap, let it dry well, refill with new litter.

Do NOT use: bleach, ammonia (smells like pee to cats), lavender disinfectants (they detest them), lemon/citrus products.

ALWAYS throw faeces in the bin (NOT down the toilet — it clogs pipes).

My cat won't use the litter tray · diagnosis

If your cat starts peeing or pooing outside, follow this decision tree:

FIRST: rule out a medical cause

If your cat was doing fine and suddenly is NOT, assume a medical cause until proven otherwise. Common causes:

• Feline idiopathic cystitis (FIC): cause #1 in young cats and males. Stress + pain when urinating. They associate the litter tray with pain → they avoid it.
• Urinary tract infection (UTI): bacteria in the urine. More common in females.
• Crystals or stones: very dangerous in males (they can cause a blockage → DEATH in 24-48h without care).
• Chronic kidney failure: in cats >7 years. They urinate much larger amounts.
• Diabetes: likewise lots of urine + thirst.
• Osteoarthritis: pain when jumping into a high litter tray.

Immediate action: vet. Take a urine sample if you can (collect it with a syringe from a clean surface). A test (~€30) rules out 95% of causes.

SECOND: stress cause

If the vet rules out medical, look for recent changes:

• Moving house / building work / new furniture
• New cat, new baby, new partner
• Frequent visitors (Christmas)
• Long absences of the owner
• Change in the family's schedule

Solutions: Feliway pheromones in a diffuser for 2-3 months, more intense play, a more stable routine, safe retreat areas (boxes, high hiding spots).

THIRD: wrong litter

Did you change recently? Go back to the previous brand. If you want to change, mix progressively 25% new + 75% old for 1 week, then 50/50, then 75/25, then 100%.

FOURTH: dirty litter tray or equipment

Checklist:

• Do you clean daily?
• Is the litter tray large enough?
• Are there enough (number of cats + 1)?
• Are the sides too high for an older cat with osteoarthritis?
• Is it in a noisy area or a thoroughfare?

In summary: the litter tray setup is critical. Size 1.5x the cat, unscented litter such as bentonite or silica, quiet location, number of cats + 1 litter trays, daily cleaning. If your cat starts going outside, ALWAYS rule out a medical cause first before assuming behaviour.