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Litter Box Problems in a Multicat Home: How to Identify the Culprit

When it comes to a litter box problem in a multicat household, the first, and often most difficult, step is to identify the furry little culprit. You may think you know which cat peed on the carpet but if you’re wrong, you could create major setbacks in the behavior plan. So how do you go about finding out which cat has turned your living room carpet into a giant litter box or has sprayed against your favorite antique chair?

The Veterinarian

Don’t automatically assume the problem is behavioral, even if your cats have been throwing hissy fits at one another. There could be an underlying medical cause for the behavior and you certainly wouldn’t want a cat to needlessly suffer. Additionally, stress can actually contribute to the onset of medical issues relating to the litter box, such as idiopathic cystitis. So get out that cat carrier because it’s time to make a vet clinic appointment.

With a multicat household, just how do you decide which cat to take to the veterinarian? If you have just two cats then it’s safest to bring them both. In a more cat-dense household, you may want to start with the most likely suspect.


Cats Under Surveillance

The most accurate way to determine which cat is eliminating outside of the litter box is to set up a surveillance camera. There are so many options on the market these days and they won’t break the budget. If you don’t already have a surveillance camera set up in your home, the most inexpensive one I’ve found is by Wyze Cam. The cameras run about $20 each. With their app, you can easily see what’s happening in the house from your smartphone and view recorded footage from the SD card. There are many other brands of cameras so choose the one that’s right for you but in my opinion, it’s well worth the investment to be able to accurately determine what’s happening when you aren’t around.


If urination or urine-marking is the problem, as opposed to defecation, you can also try identification through the use of fluorescein dye. This ophthalmic dye is used to detect problems on the surface of the eye but it has also been given orally to help identify which cat is urine-marking in a multicat household. The fluorescein will cause the urine to fluoresce under a woods lamp. You can have your veterinarian put the fluorescein in a capsule for you to administer to your cat. The problem with fluorescein is that it isn’t 100% reliable when it comes to causing urine to fluoresce.

Defecation Identification

The surveillance  camera is your best tool but some veterinarians also suggest that clients add a few shavings of a non-toxic, brightly colored crayon to a cat’s food to see if it shows up in the feces after elimination. Don’t use this method without specific instructions from your veterinarian.

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Cat Confinement

A method many cat parents use is to confine one cat away from the others to see if the problem persists. The problem with separating a cat is it’s unreliable because the confined cat may be causing the stress to the cat who is actually doing the spraying and the behavior may stop if the two cats are no longer sharing space.

What to do After You’ve Identified the Cat

Once you know which cat is engaging in the behavior, then it’s time to begin appropriate behavior modification. Treating a litter box problem is very individualized based on case specifics. Basically though, you’ll be working on two areas: 1) the litter box set-up, and 2) environmental factors. In a multicat household you have to make sure there are enough litter boxes and that they’re located in various areas around the home. They also have to be the right size and type for each individual cat. Some cats will have specific substrate preferences as well. You also need to address any multicat tension and make sure everyone feels as if they have enough security and safety in the environment.

Need More Information?

Common mistakes people make when trying to solve a litter box problem

Is the litter box in the right place

Why cats develop negative associations with the litter box

Keeping the peace in a multicat household

Why cats spray

For more specifics on addressing litter box problems, you can also find the latest information in Pam’s latest book, CatWise.

catwise top tips from the expert America has trusted for more than 35 years




We’re sorry but Pam is unable to respond to questions or remarks posted in the comment section. If you have a question about cat behavior, you can find many answers in the articles Pam writes for the website as well as in her best-selling books.








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