House Soiling in Cats: Synopsis

What is house soiling?

House soiling, sometimes referred to as undesirable or inappropriate elimination, is any urination or defecation that occurs outside the litter box. There are two main categories of house soiling: toileting outside the litter box and marking behavior. A cat may soil for either reason, or sometimes for both reasons.

House soiling related to toileting may occur because of an unpleasant litter box experience. If the litter box does not meet their needs, a cat may look for a more suitable location to urinate or defecate. For example:

• Cats that are very concerned with cleanliness may avoid going into a soiled box. 
• Cats may dislike the scent or texture of their cat litter. 
• Cats that experienced physical pain while using their litter box might believe the box caused their pain
•  A disturbance, such as a boisterous dog or noisy child, may drive a cat away from their box.

House soiling related to marking is not related to a cat’s need to urinate or defecate. In fact, scent marking is a normal way for cats to communicate.  Urine and feces contain chemical signals, known as pheromones, which convey information about a cat’s emotions, social status, sexual status, and health. Cats that mark their environment typically continue to use their litter box regularly. Marking may occur when:

• The cat is fearful, anxious, or frustrated.
• There are social stressors in the home.
• The cat feels threatened by an outside cat or person.

What should I do if my cat is house soiling?

If you notice your cat repeatedly urinating or defecating outside the litter box, the first step is to schedule a veterinary examination. A physical examination may reveal signs of discomfort—cats are very good at hiding their pain. Diagnostic testing can help identify medical conditions that contribute to house soiling. For instance, some illnesses cause a cat to produce larger amounts of dilute urine, which can quickly soil the litter box. A soiled litter box is not appealing to a cat that is particular about cleanliness, and they may seek an alternative location. 

Similarly, inflammation in the gastrointestinal tract can change the amount or frequency of stool passed. Some illnesses cause discomfort during elimination. Sensitive cats may associate this discomfort with being in the litter box and may avoid the litter box even after the medical condition has resolved. A veterinary behaviorist can help create a treatment plan that helps your cat form a more positive association with their litter box.

How is a behavioral cause determined?

The first step is to keep track of the house soiling behavior. A written journal can help document both house soiling and litter box use. The journal can include any unusual changes in your cat’s routine or overall behavior, health, or diet. Here are some important questions:

• How often does your cat use the litter box?
• How often do you find urine or stool outside the litter box?
• Where does your cat soil? Is it very near the litter box , in a hidden corner, in the middle of the room, or near a window or door?
• What surfaces does your cat use when urinating or defecating outside the litter box?
• Does the behavior occur at a certain time of day?
• What types of litter boxes are in your house, and where are they located?
• What type of litter do you use, and how often do you clean the boxes?

Cats are very sensitive to their physical and social environment. A veterinary behaviorist may ask you to describe your cat’s daily routine and to provide photographs of the litter boxes and your home environment. It is particularly important to describe your cat’s relationship with family members, including other household cats and dogs. With this information, a behaviorist can assess whether anxiety or frustration is contributing to your cat’s house soiling.

How can I make the litter box more appealing to my cat?

Sometimes, house soiling is uncomplicated, and a few simple changes can resolve the problem. Consider the litter box experience from your cat’s perspective.

• Is the box clean? Scoop out boxes once or twice daily. If you cannot clean that often, consider adding more boxes.
• Did you recently change the litter type or depth? If so, try adding a second box to compare your cat’s preferences for different litters or litter depths. See “What is a litter box preference test?” below.
• Is the box big enough for your cat? Most cats like boxes at least 1.5 times their body length.
• Can your cat get to the box? Be sure there are no children, dogs, or other cats that could ambush your cat on the way in or out of the box.
• Do you have enough boxes? A general guideline is one box per cat plus one extra. In a large home, you may need additional boxes to ensure that your cat always finds a vacant and clean box without having to travel far.

Sometimes, cats have a strong preference for eliminating in a particular location. In many cases, it is convenient and effective to place a box in that location. If your cat uses this box regularly, you may eventually be able to move it gradually to a spot that is more convenient for you. 

If you cannot put a box in your cat’s preferred spot, you may be able to change the function of the area from a toilet to a feeding or play area: place a food dish, a food-filled toy, or a favored toy in the area. If your cat is soiling in an area that they do not typically use for any other reason, you may be able to block access to the area using a gate.

What is a litter box preference test?

Some cats are very particular about their litter box experience. To find out what they like, it can be helpful to provide a variety of boxes and litters—a cafeteria experience. For example, test your cat’s preference for different litter types by providing two or more identical boxes with different litters inside (e.g., clumping versus non-clumping).

If your cat does not choose either litter, try offering the material or surface on which they have been eliminating (e.g., a piece of carpet, towel, floor tiles, soil, or even an empty box). You can also test their preference for litter depth or for a box with or without a liner. Some cats prefer a shallow depth of litter for urination and a deeper depth for defecation.

Once your cat’s favorite litter or surface has been determined, place it into different types of boxes to test whether your cat has a preferred box style. Offer two or more different boxes, such as covered versus open, different sizes, or standard versus self-cleaning.

What if my cat uses the litter box but also eliminates elsewhere?

If your cat regularly uses the litter box and also eliminates in other locations, the house soiling may be related to marking. If you suspect your cat might be marking, it is best to have a professional assessment to determine the underlying reason for the behavior. A behaviorist can identify and treat a cat’s underlying fear, anxiety or frustration.

When cats are emotionally uncomfortable, they may hide, freeze, stare, or choose high resting spaces. Keep track of the timing and location of any soiling, note any out-of-character behaviors or changes in social interactions, and consider whether there have been any changes in your routine. For example, if you start a new job that keeps you away from home longer and delays your cat’s dinner, that change in routine may cause some cats to mark. Other cats mark when they are hungry or left alone.

Be sure that your cat is getting plenty of interactive playtime and has access to many interesting activities and areas to explore. Synthetic feline pheromone products, such as Feliway Optimum®, may be helpful if placed in target areas. Ask your veterinary team which product to use and where to place it.

Should I confine my cat?

Confinement should be kept to a minimum and done with care. When you are home to supervise, your cat should be free to enjoy your company and your home. If confinement is needed, ensure the area is enriched and comfortable—include toys, food, water, cozy resting spots, and a litter box. Cats that are distressed when confined are at risk of developing physical and behavioral illnesses.

If your cat has been diagnosed with marking behavior, confinement can make it worse, because your cat may be even more motivated to communicate (i.e., mark) when they return to their main living space.

What should I do if I catch my cat eliminating or spraying?

If you catch your cat about to eliminate, you may be able to gently distract them. Do not scold or otherwise try to frighten them. Cats are very sensitive to any form of punishment, even verbal reprimands. Punishment can cause fear and can damage your cat’s trust in you.

A novel sound can often be used as a distraction, and you may then be able to lure your cat to the room with a litter box. It is sometimes possible to lure a cat directly to the litter box and then step back—but be careful not to frighten your cat or the box will become even less appealing.