Litter trays

Cats are fastidious about where they toilet, and most problems with litter trays come down to the number of trays, where they are and how clean they are kept. Even cats that go outdoors benefit from a tray indoors, and kittens, indoor cats and elderly or unwell cats depend on one.

How many and what kind

The usual guide is one tray for each cat plus one extra, placed in different parts of the home. Trays set side by side count as one in the cat's eyes.

A tray needs to be about one and a half times the length of the cat, so that it can turn and dig. Kittens and arthritic cats need a low side to step over. Some cats prefer the privacy of a covered tray and others refuse one; a hood also holds smells in, which can put a cat off unless it is cleaned often.

Litter

• Clumping clay forms solid lumps that are lifted out, leaving the rest clean.
• Non-clumping clay absorbs urine and is changed completely more often.
• Silica crystals are light and very absorbent.
• Wood, paper and plant-fibre pellets are biodegradable and low in dust.

Given the choice, most cats prefer a fine, sand-like, unscented litter about 3 cm deep. A new kitten is started on the litter it used with its mother, and any change is made by mixing the new type in gradually.

Where to put the tray

A quiet corner that the cat can reach at any hour is best, away from food and water bowls, the cat flap, washing machines and busy doorways. Cats avoid a tray where they feel exposed or might be ambushed by another pet. In a house on several floors, a tray on each floor helps older cats.

Cleaning

Solids and wet litter are removed at least once a day, and the whole tray is emptied and washed about once a week with hot water and a mild, unscented detergent. Strong-smelling disinfectants put cats off, and those containing phenols, which typically turn cloudy in water, are poisonous to them.

Used litter goes in a tied bag in the general waste. Cat faeces are not flushed, even with litter sold as flushable, and are not added to a garden compost heap.

Cat faeces can carry the parasite that causes toxoplasmosis, which is a risk to unborn babies. Pregnant women are advised to have someone else empty the tray or to wear gloves and wash their hands afterwards. Emptying it daily lowers the risk, because the parasite's eggs take more than a day to become infectious.

Teaching a kitten

Most kittens have learned to use a tray from their mother by the time they are rehomed. In a new home the kitten is shown the tray on arrival and placed in it after meals and on waking. Keeping it in one room with the tray for the first few days makes mistakes less likely.

A kitten is never punished for an accident, which teaches it only to fear the person. The spot is cleaned thoroughly with a solution of biological washing powder, rinsed and dried; cleaners containing ammonia smell like urine to a cat and draw it back.

When a cat stops using the tray

A cat that suddenly toilets elsewhere is first checked by a vet, since cystitis, kidney disease, arthritis and other illnesses are common causes. A male cat that strains in the tray and passes little or no urine may have a blocked urethra, which is an emergency.

Where the cat is healthy, the cause is usually the tray itself, a dirty or scented litter, a new position, or stress from building work, a new pet or conflict with another cat. Spraying small amounts of urine on vertical surfaces is scent marking, a different behaviour, and is discussed under keeping more than one cat.