Cats are extraordinarily fussy and tend to go to the toilet outdoors in relatively open and unused areas. Unless they are spraying or marking (deliberately leaving their scent as a territorial marking for other cats), cats carefully cover their waste and move on.

Asking cats to use a litter tray is asking them to go against their instincts. So it's hardly surprising that the most common problem reported by owners concerns their pets not using the tray.

It is important not to give your cat any reason to avoid using the litter box. Keep the box clean and place it where your cat prefers to use it. You may even need to add more litter boxes, including one at the target location.

• Most kittens are litter-trained by the time you get them - they learn to use a litter tray by copying their mother. Kittens that sniff, scratch, or crouch in a corner, should be gently lifted onto the litter tray.
• Choose a litter box that is easy for your kitten to use. If necessary, improvise for the first few weeks with a shallow, disposable container.
• Supply at least one box plus one for every cat in your household. Place each one in a quiet, low-traffic corner with easy access.
• Keep the litter tray away from your cat's food, in an easily accessible but private area. Avoid damp, dark basements, distant bedrooms, or areas with noisy washing machines, close to traffic etc.
• Choose a litter tray that is deep enough to keep cats from scattering litter when they dig, and large enough so they can make a complete turn.
• You can use an open tray, but for cats who want more privacy choose a hooded litter tray with a carbon filter to minimise unpleasant smells and litter spill.
• Cats prefer clumping, ‘scoopable’ litters to other types. Remove the soiled litter with a scoop, leaving the rest of the litter fresh and dry.
• If your cat has come to you from another home, find out what litter they used there. Some cats refuse to use a litter type they don't like.
• Fill the tray to the depth recommended by the manufacturers of the litter and place the litter tray on an easy clean surface. If you change from one type of litter to another, recheck the depth recommendation as it varies between the different types.
• Remove soiled litter at least daily. Once a week, empty the tray completely and wash it with hot water and detergent. Avoid disinfectants as some are toxic to cats.
• If you're pregnant, never handle soiled litter because of the risk of toxoplasmosis.
• Never leave your cat indoors without a litter tray. If your cat holds their urine in for long periods, bacteria will breed in the bladder, causing cystitis.
• House soiling can also be due to a physical problem such as feline lower urinary tract disease (FLUTD), a painful and potentially fatal problem if the flow of urine is blocked.
• Frequent trips to the litter box, straining, dark-coloured or reddish urine, house soiling, distress calls, and excessive grooming near the groin can be signs of FLUTD. Always contact your vet if you suspect any health problems.