Experienced and professional animal trainer provide their insights in answering this question :
A. If this is a bunny I’m wondering if bladder stones have been ruled out with an x-ray? Rabbits do get bladder and sometimes kidney stones, and it’s something I would investigate especially if Bun has always been litter box trained and suddenly he’s not.

How to Identify Common Pet Problems ?

Our sources include academic articles, blog posts, and personal essays from experienced pet care professionals :

The most common reasons a cat urinates outside of its box: Urinary tract infection. Idiopathic cystitis. Increased urine production such as diabetes or kidney disease.
Cats that are neutered or spayed will urinate outside of their litter box when something is wrong, including: Health issues. Health issues associated with not using the litter box include bladder stones, diabetes, urinary tract infections, and kidney disease. Stress related to a change in their environment or routine.
Marking Behavior

Marking behaviors can include both urine spraying and depositing feces (also called middening). Unneutered male cats and most unspayed females will mark as part of their normal sexual behavior. Spaying and neutering can dramatically reduce this behavior.

Inappropriate elimination can be caused by illness, anxiety or external changes in their environment. Be sure kitty gets checked for urinary tract infection, because urinating outside the box is a common symptom.
Marking territory with urine is your cat`s way of dealing with stress. They feel anxious and are trying to relieve their anxiety by staking out their boundaries.
Cats with UTIs try to urinate very frequently, they may pass only small amounts of urine, they may strain to urinate, they may cry out or whine when urinating, and there may be blood visible in their urine. Urinating outside of the litterbox is also a red flag that something is wrong in the bladder.
Finally, never punish your cat for spraying in your home or peeing outside of the litter box. This can cause your feline to become more stressed and make the situation worse. Frequent urinating outside of the litter box is often due to health issues, stressors, or litter box problems.
Cleaning the area thoroughly with vinegar first and then applying an enzyme treatment will break down and evaporate the uric acid and your home will be free of cat odors. Vinegar and enzyme cleaners work on all surfaces: hardwood floors, carpets, mattresses.
That`s because the surgery removes his testicles, where the hormone production occurs. It can take up to six weeks for the hormones to work their way out of the body, so if Spiffy is recently neutered, his behavior might still be influenced by residual hormones.
The most common symptoms of urinary tract infections in cats include straining to urinate, reduced amounts of urine, not urinating at all, pain or discomfort when urinating, passing urine tinged with blood and urinating around the house, outside of the litter box.
Recovery and Management of UTIs in Cats

Most cats will fully recover within 7-10 days of developing a urinary tract infection, but they may need to remain on a canned diet for longer. Your vet may check a urine sample after treatment to determine if all the bacteria are gone.

Cats who have a urinary tract infection are likely to drink more water as they try to flush the infection out of their bodies. They may urinate more often or, on the other hand, may not be able to urinate much at all when dealing with this problem.
For a short time after a Spey, small cats can be lacking in body fluid and therefore less likely to urinate out (dehydration). Kidney problems are a much less common possibility.
Urinary Tract Infections (UTI)

A UTI is an infection caused by bacteria in your cat`s urinary tract and is the most common cause of frequent urination. You may notice your cat is trying to pee but it only able to go a little at a time.

Apple cider vinegar can also lower the pH in your cat`s urine, getting rid of and preventing any harmful bacteria. Add half a teaspoon of apple cider vinegar to your cat`s food each day. To reduce the bitter taste, you can mix it in with chicken or beef broth.
As mentioned above neutering your male cat helps stop or limit undesirable behaviors associated with testosterone (sexual behaviors). These changes can occur immediately or several weeks after their procedure. The age, breed, or environment of your kitty doesn`t typically make any big effects on these changes.
Many cat owners wonder if their neutered or spayed cat will still have the urge to mate or exhibit sexual behaviors. The short answer is no, probably not. However, there are some exceptions to this. Sexual activity in sterilized cats could be related to a health issue.
The urine shouldn`t be cloudy or difficult to see through. Changes in color (dark or light), cloudiness, or particulate matter (floating debris) are most often associated with bladder or kidney conditions. If you have an adult, spayed or neutered cat, chances are your feline`s urine smell isn`t too strong.
Stress in cats can often lead to a number of health concerns, including a urinary tract infection. Feline Lower Urinary Tract Disease (or FLUTD) refers to several ailments that affect a cat`s bladder or urethra, such as bladder stones, urethral blockages, idiopathic cystitis, UTIs, and more.
Signs associated with these conditions include hiding more, loss of appetite, vomiting, becoming aggressive if touched, or acting lethargic.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

Q. I have a cat that defecates in the litter box but always urinates outside the box. It is very annoying.
ANSWER : A. Inappropriate elimination in cats is often a behavioral problem rather than a medical problem, so the first step is to have him seen by your vet to eliminate any kind of illness or condition as a cause for his eliminating outside the box.

If medical issues are ruled out, take a look at other reasons. Has there been a lot of unusual activity? Has you cat been left at home or boarded? Is the litterbox in a busy area? Has anything happened recently in this area to make him reluctant to use it again? Is there another cat, pet or person that is preventing him from getting to the box? Have you changed it from a hooded to an open box, or vice versa? Is it big enough? Have you changed the type or brand of litter? Is there something attractive about the spot he uses? Cats dislike disturbances to their routine and may act out to express their dissatisfaction.

The general rule is one litter box per cat in the household, plus one. That way each cat can have a place of their own to go in case the box is occupied or another cat has claimed it as territory. They should be scooped daily, if not more often and changed completely weekly, washed with soap and water only. You can offer one kind of litter in one box and another kind in another to see if there is a preference. I don’t recommend the crystals, it makes a hissing sound when wet that startles some cats and make them reluctant to use it again. The litter boxes should be located in a quiet, low-traffic area so that the cat can use them in peace. Make sure any other pets or people aren’t giving them a hard time around or in the litter box. It may take some investigation and experimentation to find your cat’s preference and accommodate him so that everyone is satisfied with the situation. And, when cleaning up pet accidents, don’t use any cleaner containing ammonia. This leaves behind a scent similar to urine.

Q. My cat seems to have lost control of her bowels and no longer uses her litter box even to urinate. She is 5 or 6 yrs and is in good health otherwise
ANSWER : A. If your cat has had a sudden change in litter box habits, it is always a good idea to rule out any underlying issues with a wellness check from your vet. Bringing in a urine and stool sample if possible can also help as tests can be run on these samples to check for common infections or parasites. If these are present, treating them usually helps resolve the problem of not using the box.

Loss of bowel control usually results in dribbling of feces or urine rather than complete accidents. If you are seeing this, it is possible that an injury to the hind end or problem with the nerves or muscles is happening and should be looked at by your vet.

If the accidents are complete (full amount of stool, big puddle of urine) your cat may be choosing not to use the litter box due to illness, a too-dirty litter, litter pans that are too tall (which may make older cats have a harder time getting in and out), or a litter substrate that was changed too suddenly. Sometimes, changing the environment your cat’s litter box is in by lowering the sides, moving food and water dishes away and returning back to a previously liked litter can help.

In any area of an accident, an enzymatic cleaner should be used. These break down urine and stool particles, making it so that your cat is less likely to be attracted to going there again. Moving stools to the litter box can also entice your cat to start going there again.

Q. My cat will not stop going to the toilet on my carpet, bed, washing pile etc.. Also uses its litter box occasionally? I don’t understand why this is?
ANSWER : A. Inappropriate elimination in cats is often a behavioral problem rather than a medical problem, so the first step is to have him seen by your vet to eliminate any kind of illness or condition as a cause for his eliminating outside the box.
If medical issues are ruled out, take a look at other reasons. Has there been a lot of unusual activity? Has you cat been left at home or boarded? Is the litterbox in a busy area? Has anything happened recently in this area to make him reluctant to use it again? Is there another cat, pet or person that is preventing him from getting to the box? Have you changed it from a hooded to an open box, or vice versa? Is it big enough? Have you changed the type or brand of litter? Is there something attractive about the spot he uses? Cats dislike disturbances to their routine and may act out to express their dissatisfaction.
The general rule is one litter box per cat in the household, plus one. That way each cat can have a place of their own to go in case the box is occupied or another cat has claimed it as territory. They should be scooped daily, if not more often and changed completely weekly, washed with soap and water only. You can offer one kind of litter in one box and another kind in another to see if there is a preference. I don’t recommend the crystals, it makes a hissing sound when wet that startles some cats and make them reluctant to use it again. The litter boxes should be located in a quiet, low-traffic area so that the cat can use them in peace. Make sure any other pets or people aren’t giving them a hard time around or in the litter box. It may take some investigation and experimentation to find your cat’s preference and accommodate him so that everyone is satisfied with the situation. And, when cleaning up pet accidents, don’t use any cleaner containing ammonia. This leaves behind a scent similar to urine.

Q. Our cat of six years has on two separate occasions has defecated on the living room rug and recently pee’d on the skirt of the Christmas tree.
ANSWER : A. Inappropriate elimination in cats is often a behavioral problem rather than a medical problem, so the first step is to have him seen by your vet to eliminate any kind of illness or condition as a cause for his eliminating outside the box.

If medical issues are ruled out, take a look at other reasons. Has there been a lot of unusual activity? Has you cat been left at home or boarded? Is the litterbox in a busy area? Has anything happened recently in this area to make him reluctant to use it again? Is there another cat, pet or person that is preventing him from getting to the box? Have you changed it from a hooded to an open box, or vice versa? Is it big enough? Have you changed the type or brand of litter? Is there something attractive about the spot he uses? Cats dislike disturbances to their routine and may act out to express their dissatisfaction.

The general rule is one litter box per cat in the household, plus one. That way each cat can have a place of their own to go in case the box is occupied or another cat has claimed it as territory. They should be scooped daily, if not more often and changed completely weekly, washed with soap and water only. You can offer one kind of litter in one box and another kind in another to see if there is a preference. I don’t recommend the crystals, it makes a hissing sound when wet that startles some cats and make them reluctant to use it again. The litter boxes should be located in a quiet, low-traffic area so that the cat can use them in peace. Make sure any other pets or people aren’t giving them a hard time around or in the litter box. It may take some investigation and experimentation to find your cat’s preference and accommodate him so that everyone is satisfied with the situation. And, when cleaning up pet accidents, don’t use any cleaner containing ammonia. This leaves behind a scent similar to urine.

Q. My cat started to pee outside the litter box. What should I do?
ANSWER : A. Inappropriate bathroom use in cats is often a behavioral problem rather than a medical problem, so the first step is to have him seen by your vet to eliminate any kind of illness or condition as a cause for his defecating outside the box.

Once medical issues are ruled out, it’s time to take a look at other explanations. Has there been a lot of activity that wasn’t normal? Were you away and your cat was left at home or boarded? Is the litterbox located in a busy area? Has anything happened recently in this area to make him reluctant to use it again? Is there another cat, pet, or person that is preventing him from getting to the box? Have you changed it from a hooded to an open box, or vice versa? Have you changed the brand of litter or kind? Or is there something about the spot he has chosen to use that is attracting him in some way? Cats dislike disturbances to their routine and may act out as a way of expressing their dissatisfaction.

The general rule of thumb is one litter box per cat in the household, plus one. That way each cat can have a place of their own to go in case the box is occupied or another cat has claimed it as territory. They should be scooped at least daily, if not more often and changed completely on a weekly basis, and washed with soap and water.

You can also offer one kind of litter in one box and another kind in another to see if there is a preference. I don’t recommend the crystal kind, since it makes a hissing sound when wet that can startle some cats and make them reluctant to use it again.

The litter boxes should be located in a quiet, low-traffic area so that the cat can use them in peace. Make sure other pets or people aren’t giving them a hard time around or in the litterbox. It may take some investigation and experimentation to find your cat’s preference and accommodate him so that everyone is satisfied with the situation.

Q. Bun is frequently urinating outside litter box. Before two weeks ago he was always using his litter box. He is neutered and bonded.
ANSWER : A. If this is a bunny I’m wondering if bladder stones have been ruled out with an x-ray? Rabbits do get bladder and sometimes kidney stones, and it’s something I would investigate especially if Bun has always been litter box trained and suddenly he’s not.

Q. My cat is pooping outside of the litter bix. He is 2 1/2. He did this as a kitten. It stopped then started about 3 months ago. Litterbox is clean.
ANSWER : A. Inappropriate elimination or house soiling can be a frustrating problem but with a bit of detective work on your part, there is hope. First, before deciding that this is a behavioral issue, any medical problems (diarrhea, constipation, fecal incontinence, pain on defecation, etc.) need to be ruled out and/or treated. If your cat receives a clean bill of health from your vet but is still eliminating outside the litterbox, then we need to consider that something about the box itself might be aversive to your cat. Cats can be quite finicky about their litterbox and toileting habits. Below I have listed common recommendations and cat preferences for litterbox use. Review the list and make any changes that could account for your cat’s aversion to defecating in the litterbox:
* Soft, fine-grained clumping litter (vs, coarse-grained, non-clumping litter)
* Unscented
* 1 – 1 1/2 inch depth (especially older cats or cats with hip problems)
* Larger pans (especially for large cats) – want to get whole body inside – poop just outside the box might mean the box is too small
* Open, non-hooded
* At least one shallow side to get in and out easily
* Easy to get to – not hidden away, preferably in areas they spend time in or near – and not near appliances that make scary, unpredictable noises (washers, dryers, refrigerators)
* Scoop minimum 1X/day – preferably 2
* Clean the litterbox with soap and water and put in fresh scoopable litter at least once/month (instead of just continuously adding)
* Some cats prefer to urinate in one box and defecate in a separate box, so you may need 2 boxes even if you just have 1 cat. Multi-cat households should have 1 box/cat plus 1 extra.

Q. Cat is deficating on rugs, not litter box. Has never done this until this year. We drove from NY to FL, could there be a connection?
ANSWER : A. Sudden changes in bowel or litter box behavior can be caused by both behavioral or medical reasons. Scheduling a wellness exam with your local vet to rule out any problems (and also to bring in a stool sample) is the best first step. Problems such as digestive upset, constipation, diarrhea or even arthritis in older cats making it harder to get into the box can all cause this problem.

If your cat checks out healthy, it is possible that stress such as another person or pet in the home, age, or environment are causing the problem. Make sure that the litter used is the same, and if it needs to be changed that it is done gradually- cats are very picky about what they like as litter. Making sure bedding, food and water are not too close to the litter can also help as cats do not like to potty near these objects usually. For arthritic cats, a step or lowered box can make getting in and out easier to allow for proper use of the box. Keeping the box clean is also a must for cats.

As for cleaning up accidents, using a product such as an enzymatic cleaner may be helpful. These products break down urine and stool particles left in the accident area, and may deter your cat from using the spot as a bathroom again.