We see a lot of cats that eliminate outside their box. It's a very stinky, frustrating problem. I'll walk you through the questions I consider in order to figure out why a cat urinates inappropriately and some of the steps we take to correct it.
First question: Is this a medical problem or a behavioral problem?
Medical problems like a urinary tract infection, bladder stones, an inflamed bladder or a bladder tumor can make a cat urinate outside his or her box. A metabolic disease, such as diabetes or kidney failure, which can make a cat drink and urinate a lot, can also make a cat urinate outside the box. Have your veterinarian examine your cat and perform the diagnostic tests deemed necessary. This will usually involve doing urine tests and blood tests. It may also involve either taking an x-ray or performing an ultrasound examination to look at your cat's bladder. If your cat is free of any medical problems, then there is a behavioral issue causing him or her to eliminate outside the box.
Second question: If it's a behavioral problem, then is your cat marking his or her territory, or does he or she have a litter box aversion or an inappropriate site preference?
Urine Marking -- Cats that are marking their territory often urinate on vertical surfaces, like walls or the back of a chair. When a cat marks (sprays), he or she will stand and their tail quivers. Even when spayed and neutered, cats can still mark their territory. Cats may mark their territory when a stray cat is hanging around, when there is a new pet or family member, or if they are stressed about something like a diet change or not enough attention.
Suggested Treatment -- First spay or neuter you cat. Second, try to identify why your cat is marking. Is there a stray cat coming around your house? Did you add another pet to the household? Have you switched foods? Have you been too busy to interact with your cat? If you can identify the cause, take steps to correct it. For example, block your cat's view of the stray with frosted window covers or put in motion sensor sprinklers to scare the stray cat away. Separate new pets and introduce them slowly. Make diet changes gradually. Try to spend more time interacting with your cat. Provide multiple feeding, perching and sleeping sites. Third, give your cat more appropriate ways to mark his territory: add scratching posts or use Feliway products, which encourage facial rubbing instead of spraying, as a cat's method of territorial marking.
Litter Box Aversion -- Cats with a litter box aversion urinate on horizontal surfaces, often close to their box. They may be upset about the actual box, its location, or the litter in it. Some cats may have difficulty physically getting in the box or may feel threatened by another pet hanging out close to it.
Suggested Treatment -- Determine what type of box your cat prefers by temporarily giving him several different litter box options and seeing which he chooses. In general, cats prefer a clean, uncovered box with a fine textured, unscented, clumping litter. Most cats do not like their box in a busy, noisy, dark or smelly area. If you have multiple cats you should have a box for each cat plus one more, in different areas of the house. Try putting the box in the location where your cat is eliminating inappropriately and then when he or she begins using it, gradually move it to the area you want him to go.
Litter box hygiene is important for any elimination problem but is especially critical for cats with litter box aversion. Clean up urine outside the box with an enzymatic cleaner such as Anti-Icky-Poo or Nature's Miracle. Scoop the box twice a day, change litter weekly and wash the box monthly with mild dish soap. Carefully rinse away all traces of the detergent as cats find the smell of cleaning products offensive.
Inappropriate Site Preference -- Some cats would rather urinate or defecate in places other than their litter box. The most popular sites for cats are soft fabric (bedding, laundry, couch) or a smooth cool surface such as a tile floor or a sink.
Suggested Treatment -- For cats with an inappropriate site preference, the goal is to make that site less attractive and their litter box more attractive. First, try changing the texture of the site. For example, you can place a vinyl carpet runner nub side up on your bed. Or put a sheet of foil, plastic, sandpaper or double sided tape on your couch. Second, change the purpose of that site: place your cat's food or water where he is eliminating. Third, block access to the elimination site by closing doors, keeping laundry off the floor or putting a potted plant in the selected area. Fourth, put the box as close as possible to the inappropriate location your cat has chosen, then gradually move it to where you want to keep it. You don't have to try these ideas in the above order -- use whichever order you think best for your cat. Finally, do everything you can to make the litter box more appealing; see the solutions for litter box aversion above for options.
For some cats, these environmental strategies are not fully effective and we also treat them with Prozac or other behavior modifying medications.
These are just some of the common causes and solutions. For additional information, one excellent resource from the College of Veterinary Medicine at The Ohio State University is http://indoorpet.osu.edu/cats/. In all cases, I recommend you discuss your cat's specific issues with your veterinarian to come up with the appropriate treatment to get your cat using his or her box consistently.
And that's the scoop on litter box problems with cats!