Each week, Dr. Patrick Tate, chief of the veterinary staff and a general practitioner at Webster Groves Animal Hospital, answers reader questions about pets. This week's question comes from Sharon Evanston.

Question: Why does my cat urinate outside of the litter box?

Answer: Inappropriate urination, or house soiling, is a common problem in cats that can be very challenging to analyze and correct. Sadly, it is the main reason that countless pet cats are given away, abandoned or euthanized. Many house-soiling issues are behavioral in nature, but others have a medical cause. The earlier you recognize, diagnose and treat an inappropriate urination problem, the greater chance there is for success. This may involve some serious detective work.

The first step is to consult with a veterinarian to see if your cat has an underlying medical issue. Feline lower urinary tract disease (FLUTD) is a frequent cause of inappropriate urination. Other conditions like urinary tract infections, kidney failure, diabetes and liver disease can also cause changes in litter box behavior. Some cats begin house soiling when they have a physical problem, like arthritis, that affects mobility and makes it difficult to enter the litter pan. Poor eyesight, old age, dementia and incontinence are also problematic. A thorough exam along with blood, urine and radiographs can rule out a health problem.

Cats are very complex and sensitive creatures and a behavioral cause of house soiling is more difficult to evaluate. Urine marking (also called urine spraying) is a different behavior than regular urination outside of the litter box. Most of the recommended treatments can be used on both issues but some work better on one or the other.

A veterinarian can assess if your cat is urine spraying his territory. Unlike regular urination, urine spraying is a form of indirect communication used by cats to announce their presence, establish territorial boundaries and show sexual availability. The cat doesn’t squat to spray (like in regular urination), but his tail lifts and quivers against a vertical surface, leaving small puddles of urine in different locations. The urine has an especially pungent odor.

Cats that spray are typically unneutered males and unspayed females, but it frequently happens in those that are spayed and neutered. Cats may mark their territory when they perceive a “threat” to their space. Pet owners have noticed the onset of urine spraying when a strange cat enters the house or neighborhood, new furniture or carpet is moved in, a cat is bullied by other pets, etc.  

Urine marking may improve when the perceived threat is removed or accepted. For more persistent cases, a synthetic pheromone (like Feliway) can be applied to household surfaces or emitted into the air. This product mimics the scent of cat cheek gland secretions, and cats (hopefully) avoid spraying on or around it. Anti-anxiety medications, in conjunction with behavior modification techniques, have also been helpful. Ideally, odor neutralizers should be applied to ALL urine marked areas before beginning any treatment. 

If your veterinarian rules out a medical or urine spraying problem, then the cat probably has “inappropriate urination” (squatting on a horizontal surface outside the litter box) resulting from anxiety or stress. Just as with urine marking, it is difficult to pinpoint the exact source of the cat’s stress. It could be a divorce, a new pet, the death of a pet, the birth of a baby, an active toddler, a recent move, a new job, remodeling, lack of stimulation, new fragrances, etc. In my experience as a veterinarian (and owner of two cats that had this problem), many cases improve with better litter box management no matter what the source of anxiety. Cats under stress often develop a “litter box aversion” to the actual box, the litter or its location.

Here are a few important litter box tips:

1. Have as many litter boxes in the house as there are cats, plus one (i.e., if you have two cats, you need three litter boxes).
2. Most cats prefer a large, uncovered box that allows a 360-degree view of their surroundings.
3. Most cats prefer unscented, finely-textured litter at a depth of about 1-2 inches.
4. Most cats prefer a quiet, private, safe location separate from their feeding area.
5. Place a litter box on each floor of the house. Avoid stairs if a cat is unable to climb.
6. Make sure the sides of the pan are lower for a kitten, elderly cat or cat with mobility problems.
7. Scoop the litter at least once a day. Once a week, clean all litter boxes with warm water and unscented soap and completely replace the litter (do not use cleaning products that contain strong fragrance or ammonia).
8. If urination occurs outside the litter pan, clean immediately and thoroughly with an enzymatic cleanser designed to neutralize pet odors.
9. Move the litter box to the area of inappropriate urination. This does not always work, but it is worth a try.  

Along with litter box changes, studies have shown that physical and mental exercise (sometimes called “environmental enrichment”) can help to reduce inappropriate urination among indoor cats. Extra playtime, stimulating “prey” toys, scratching posts, window boxes, elevated perches, leash walking and even kitty-friendly DVD’s have proven effective.

Your veterinarian or a qualified animal behavior specialist can work with you to design an individualized treatment plan for your cat. With commitment and patience, even the most persistent house-soiling issue can be helped. For more information, I recommend Think Like a Cat: How to Raise a Well-Adjusted Cat- Not a Sour Puss by well-known cat behavior consultant Pam Johnson-Bennett. Her Cat Behavior Associates website is also a helpful resource.  

Do you have a question for Dr. Tate? Email your questions to Webster Groves Patch Editor Sheri Gassaway. Be sure to attach a photo of your pet, and we'll feature it along with your question!