Did you know inappropriate elimination -- i.e. outside of the litter box -- is a common concern and is one of the most frequent reasons cats are relinquished to animal shelters? Fortunately, many litter-box problems can be resolved with simple changes and some sleuthing to determine the root of the problem.
First consult your veterinarian: Any time there is an abrupt behavioral change in your pet, it is essential to first visit your veterinarian to determine if there is a medical reason. A change in litter-box habits may be the result of a urinary tract infection or gastrointestinal upset. A cat experiencing a health problem may quickly associate the litter box with the painful feeling experienced when trying to relieve himself. If this occurs, your kitty may develop an aversion to the litter box and choose an alternative place to potty -- usually one that is problematic for humans.
Litter-box aversion: Litter-box aversion may develop if your cat has experienced an unpleasant experience in the litter box. This could be the result of painful elimination in the box due to a health problem or a frightening experience such as a loud noise or altercation with another cat or a dog while using the box. If your cat has developed an aversion to the litter box, replace the entire box, place it in a new safe location and use a soft litter type.Cleanliness
One of the most important things to consider is the cleanliness of your cat's litter box. An increase in your scooping and cleaning of the litter box can make a world of difference to a cat experiencing problems using their box. Boxes should be scooped daily and fully cleaned every few days. Avoid heavy chemicals for cleaning; cats have an excellent sense of smell and the harsh scents may cause them to avoid the box.
Litter box size and style: The litter box should be large enough for your cat to comfortably move within and turn around. A good rule of thumb is to use a litter box that is 1 and 1/2 times the length of your cat. If your commercial litter box seems a bit small, consider using a large, shallow plastic bin instead to provide your kitty plenty of room. The style of your litter box may be an important consideration as well. While some cats seem to prefer the privacy of covered boxes, other cats tend to avoid covered boxes altogether.
Litter preference: Cats often develop surface preferences for elimination. Many cats prefer soft surfaces for potty material; therefore, it may be helpful to try a fine litter that is comfortable under kitty feet. Keep the litter fairly shallow in the box so the entire surface is covered, but isn't too deep.
Litter box number and location: Another simple and beneficial option is to add additional litter boxes in other locations that are both convenient and easy for your cat to access. Even if you have only one cat, multiple litter boxes placed throughout the house with one on each level is best. It is essential that boxes are places away from frightening sounds or objects (i.e. washer/dryer or vacuum cleaner locations may be scary).
If you also have a dog, check to make sure the litter boxes are placed in a low traffic location that is safe and secure from the dog, but also convenient for your cat. Some cats are averse to using the same litter box as their housemate. So if you have multiple cats, make sure you have at least as many litter boxes as you have cats. Your best bet is to have one more litter box than you do cats.
For additional support, seek help from a certified applied animal behaviorist, veterinary behaviorist or feline behavior consultant.