Uh oh...Kitty is no longer using his/her litter box. What happened?
That IS the question!! There are a number of reasons cats may no longer use their litter box. It would require an investigation into each particular case to know for sure, but there are a few general reasons that many cats do leave their litter boxes. These reasons can be behavioral or medical.
Always....please always, have kitty checked for medical issues if it is no longer using the litter box. Medical issues must be ruled out before we can consider behavioral issues. Even if kitty left the box for behavioral issues, sometimes medical issues can ensue.
Non-Medical Possibilities
If your cat is defecating outside the litter box, one of the first things to consider is the size of the box. There have been cases of cats given only covered boxes that are too small and, not having sufficient space, their rear end remains outside the box even while their front end is in the box. Since all four feet are in the box, the cat likely believes it is fully inside. Unfortunately, with the hind end still outside the box, it actually eliminates beyond the barrier of the box.
Should the cat not consider the location or surrounding circumstances safe, it may look for a safer local. Placement of the litter box in areas such as behind a corner or piece of furniture will be considered unsafe by kitty and the search will begin a less frightening place to eliminate. Even if the litter box set up has clear visual path, kitty may have been surprised by the family dog waiting to grab a kitty crunchy, or a family pet or child has ambushed kitty while leaving the box. These happenings are very unnerving for kitty. If the litter box has been placed near an appliance, it could be that the motor started up and frightened kitty. That fear can drive kitty from a litter box location once thought to be safe.
There has been some research into the idea of phermones and cat behavior. You may know Feliway (products page) is sometimes used to calm cats and help them return to the litter box (do not spray the litter box with it, but keeping a Feliway Plug-In in the room may help). Some researchers believe that Fear Phermones may have been left behind by a cat that was frightened during elimination. Any time kitty returns, they are confronted with those same fear phermones and may choose to no longer eliminate in that particular litter box. Cleaning the area of those phermones may help to bring the cat back to the box. This holds true for urination and defecation beyond the litter box.
Urination outside the box can be caused by many of the same issues as mentioned for defecation. But we also must decide if the cat is urinating or marking territory... If the cat can be seen during the act of elimination it will be helpful. If not, examine where and how much urine is being eliminated. Is the amount similar to a full urination or a smaller amount. Is the pattern more vertical or horizontal in nature? Is it near windows or doorways? When cats "mark" with urine, they typically stand, so the urine may leave a puddle on the floor, but you will be able to trace it to an area that is vertical as well. Generally it will be a smaller amount of urine. Because cats do mark to claim territory, this could result from uneasy relations within the home or perhaps a cat (most likely) or dog entering the cat's home yard (that's why the urine may be near windows/doors.
Let's not forget, one of the chief reasons cats will choose to leave a litter box is due to the lack of cleanliness. Cats are very clean creatures. If they approach a dirty litter box (and to some cats, having one elimination in the box can be considered disgusting!) and consider it to be too dirty to enter, they will choose a "cleaner" location to eliminate.
Medical Possibilities
Medically speaking, if a cat has had pain upon elimination, the memory of such pain can send them searching for a location that does not illicit such pain. Defecation can be painful if cats are having diarrhea, are constipated or even have anal gland issues (blocked, infected or full).
Many of you likely realize that urination can be painful if cats have a urinary tract infection. Your veterinarian may check a urine sample for bacteria or even urinary stones/crystals and give the appropriate treatment. However, be sure that your veterinarian is aware of other urinary issues such as Sterile Cystitis and FLUTD (Feline Lower Urinary Tract Disease) and Idiopathic Cystitis. No bacteria or stones will be found upon review of the urine sample. Some veterinarians may say, "no issues found so it must be behavior." If your veterinarian is not familiar with these other medical issues, change veterinarians and find one more familiar with feline medical issues. These conditions are all very painful; remember, pain can drive a cat from the litter box. You may find that your cat is urinating small amounts in several places. Kitty will many times urinate in small amounts because due to their condition, they have a feeling of urination urgency, even though their bladders are not full. You may even notice that the urine is blood tinged which will let you know there is a significant issue, even though no urinary crystals (stones) or bacteria are found on analysis. If your veterinarian has an ultrasound machine in their office, they can look at the bladder lining to confirm it has thickened or changed. Always be the advocate for your cat; don't be afraid to question your veterinarian to obtain thorough information.
Other reasons cats may be urinating outside the box are because they urinate too often or at greater amounts than they did previously, making for a fuller box and need to find a clean place to eliminate. So, why would cats need to urinate so often if there is no bladder issue? There are several other medical conditions that could create this need; diabetes, kidney disease, hyperthyroidism, among others. Many times their body is trying to clear itself of contaminates related to the disease process, causing the cat to drink more and subsequently urinate more. Some medications, such as steroids, will create a greater thirst, consumption of water and ultimately more frequent and larger urinations.
Again, If your cat has left the litter box, it is ALWAYS best to have kitty examined by the veterinarian to rule out any medical issues that could be the cause. If kitty is cleared of medical issues, then we can begin to investigate other environmental/behavioral reasons. Whether kitty left the box for medical or behavioral issues, using Zero Odor's Litter Box Spray (products page) can help bring kitty back to the box. Research has shown that cats returned to the litter box in over 90% of cases studied.
Importance of Cleaning
Important to consider: Once cats have left the litter box, it is important to address the areas where they have urinated/defecated. There are many cleaners on the market, some much better than others. (I would not recommend Nature's Miracle or Simple Solutions as they have proven not very effective.) I like Fizzion, which is an enzymatic cleaner and also an all around good household cleaner. It cleans urine, feces, vomit, blood, etc.. If you are unsure of all the places your cat may have urinated, you can obtain a black light (there are flash light models or you can use the "stink finder.") to illuminate walls and floors. Urine will "glow" yellow. It's a good way to ensure you have cleaned the area well also. Leaving the areas only partially clean can draw kitty back to "refresh" their scent.
TWO MORE NOTES OF IMPORT:
1) Keeping litter boxes clean, eliminating stress and creating an enriched environment can keep most cats happy and consistently using their litter boxes.
2) PLEASE, NEVER PUNISH YOUR CATS. Kitty is either dealing with a painful medical condition or likely already under some form of stress. Punishment doesn't work for cats. They don't understand why you are doing this behavior and only see it as emotionally (and physically) hurtful. It can be detrimental to the bond you have with your cat as well. Understand that your cat is not "acting out", "mad at you" or "being resentful", your cat is under physical and/or mental stress and punishment will only add to that stress. Be patient, have your cat examined by a veterinarian and work through what might be going on medically or behaviorally to help kitty if the vet gives a clear medical report.