Don’t you wish you could either read your cat’s mind or teach them to speak English? That might help you understand some of their behaviors that seem bizarre to us humans. 

Like why is your cat peeing in the sink (or the bathtub or shower)? Why would a perfectly sane cat who used the litterbox last week without complaint suddenly deposit smelly urine where you brush your teeth???

Many people call this problem “inappropriate urination.” I hate the term because it’s really only inappropriate in a human’s opinion! The cat probably thinks it’s perfectly appropriate to pee in the tub under the circumstances they’re dealing with!

When a cat owner reports their kitty has suddenly started peeing in the bathtub, sink or shower the first thing I do as a vet is to check for signs of bladder inflammation, infection and stones. Even if the urine appears normal to the naked eye, there might be traces of blood, crystals or protein on a urinalysis test. And usually, bladder stones are only detected once an Xray is done. 

Let’s talk about how veterinarians approach this problem… 

Most Common Reasons Cats Pee in the Bath

Urinary Tract Disease (Often WITHOUT Infection)

The first assumption most people make about a cat who’s peeing in the sink is that they have a “UTI” or urinary tract infection

While UTIs do happen in cats, it’s far more common for cats under the age of 10 years to have bladder inflammation without any infection. In one study, only 2% of cats under 10 years old with bladder symptoms actually had a bacterial or fungal infection. (3)

Feline Lower Urinary Tract Disease (FLUTD) is the most common cause of bladder inflammation in cats under 10 years old. FLUTD symptoms are caused by inflammation of the bladder. The most common observations made by cat owners are increased urgency and frequency of urination and blood in the urine. Many studies have tried to identify the underlying cause of FLUTD, but to date, it’s still unknown.

Cats with this problem often stop urinating in their litterbox. Some vets believe cats with FLUTD associate the litter box with pain so they pee somewhere else. It could be that cats find the cool surface of the bathtub, sink or shower to be soothing. I will tell you I’ve heard many, many cat owners report that their pet pees in one of these places when they have a FLUTD flare-up. 

Marking Territory

Cats use urine to mark their territory or show other animals where they’ve been. It’s normal even if we humans find it very nasty!

Typical urine marking involves spraying urine onto vertical surfaces. Both cat sexes may engage in urine marking. It’s much more common in cats who have not been spayed or neutered, but occasionally even spayed females and neutered males do a little urine marking.

If your cat is peeing on a horizontal surface, it’s less likely to be part of marking behavior. Try to catch your cat when they to it. If you see them scratch the surface and then release a moderate to large amount of urine, they’re probably not marking. 

If they release only small amounts of urine on a horizontal surface, they more likely suffering from bladder inflammation.

It can get confusing to interpret what they’re trying to tell you because stressed cats are more likely to mark with urine. But they’re also more likely to suffer from bladder inflammation. Your vet can do a urinalysis to help distinguish between marking and bladder pain.

2 tabby and white kittens (why is my cat peeing in the sink?)
Kittens are naturally attracted to using a clean litterbox.

Dirty or Uncomfortable Litter Box

Indoor litter trays are a human invention that allows cats to pee and poop in a way that’s convenient for us. I’m amazed at how well most cats go along with our desires and use this “toilet” even when it’s not that appealing or convenient for them. 

To avoid having to deal with the mess and odor, cat owners place the litterbox in out-of-the-way places like the laundry room. Then put a cover on it and fill it with strongly perfumed litter. Some people even add machinery to automatically clean the box right after the cat uses it. Great for human convenience, but it’s certainly not what a cat would choose “in the wild.” 

Cats are turned off by stinky, full litterboxes as much as we are. So if it’s grossing you out, imagine how your cat feels when they have to get in there and walk in the filth!

Litterbox size, shape and location are all important considerations if you want your cat to reliably toilet in your preferred area. 

Cats like larger litter boxes than most humans give them.(2) It’s possible your cat pees in the bathtub (or other bathroom vessels) because it’s larger and cleaner than their assigned litterbox! 

Researchers found that cats with a history of peeing or pooping outside a litterbox don’t scratch as long as cats who always use a litterbox.(4) A possible explanation for this finding is that cats don’t scratch in the litterbox because it’s uncomfortable for whatever reason. And because it’s uncomfortable, they find other places to pee and poop.

6 Things Cats Hate About Litterboxes

Of course, these are common but not universal truths. If your cat is peeing or pooping in places you don’t want them to, think about the things on this list…

  1. Sharing a litterbox with other cats–provide one more litter box than the number of cats living in your home.
  2. Litter material is uncomfortable–identify your cat’s preferences by creating a temporary kitty litter “cafeteria.” Do this by filling several clean boxes with different types of litter to see which your cat uses most often. Try different textures of litter. Also, try Dr. Elsey’s Cat Attract litter–this stuff works!
  3. Too much perfume–scented cat litter appeals to humans but probably not to cats who have a much stronger sense of smell. Perfumed litter doesn’t really cover the smell of a dirty box anyway, so I recommend using unscented litter.
  4. Scary or out-of-the-way location–keep a litterbox where your cat spends most of their time. Place litter boxes on all levels of your house. 
  5. The litterbox is too small–you pretty much can’t go wrong with a larger litterbox. Try to get one that’s at least 1.5 times the length of your cat. Also, covered and top-entry boxes are not recommended by most cat experts but you can experiment to see what your cat prefers. Litterboxes that are about 8-12 inches deep work well to hold a 3 to 4-inch litter depth and contain scratched-up litter. You can cut a lowered entry hole if your cat has mobility issues.
  6. Dirty/stinky litterbox–you might not like this, but the truth is the only way to keep a litterbox from smelling bad is to remove pee and poop frequently. If your cat uses the box 4-6 times a day, that’s a lot of smelly waste just fouling up the area. For best results, scoop out all eliminations at least once a day. If you fill the box about 3 to 4 inches deep with clean litter, scooping is easy and less gunk will stick to the inside of the box. If stuff is stuck to the box, be sure to clean it off so the smell doesn’t linger. Finally, completely empty the box and clean it with soap and water weekly. Refill it with a fresh, deep bed of litter.

How to Stop a Cat from Peeing in the Bathtub

Identify and Treat Diseases

I know your cat probably hates going to the vet clinic! But that’s a separate problem that can be overcome. But there is really no way to diagnose and treat urinary tract disease without a vet’s help. You always have the option to find a vet who makes house calls if your cat gets stressed by travel. 

Your vet will rule out physical diseases by doing blood tests, a urinalysis, and X-rays. They may prescribe medications or a prescription urinary diet if the cat has bladder inflammation.

If no physical problems are found, the next step is to address potential behavioral causes. I’m fortunate to live where we have some great veterinary behaviorists as well as layman pet behavior specialists who specialize in cat toileting problems. It can be so helpful to have one of these experts come to your house to assess your setup. Ask your vet for guidance on this.

Here are a few more general tips I give to clients who are facing cat urination challenges: 

Help Your Cat De-Stress

A cat’s entire life can be stressful if they are confined to a house or apartment. When there are numerous cats involved, some level of stress is almost unavoidable.

By providing environmental enrichment for your cat, you can make his or her life happier and less stressful. You don’t need to turn your whole house into a cat-friendly amusement park. Even a few strategically placed climbing structures, hidey holes, and interactive food toys can drastically improve a cat’s mood.

OSU’s veterinary school has some good resources to get you started on their Indoor Pet Initiative website. 

Punishment Is Never the Solution

It’s reasonable for a cat owner to become annoyed when their cat refuses to use the litter box. However, it’s critical not to physically or verbally punish cats for peeing in places where you don’t want them to.

Spray bottles, spanking and shouting will not solve the problem. Cats don’t learn desired social behaviors well from being punished. In fact, you will probably make the problem worse by scaring and confusing your cat.

Manage Access to Problem Areas

I’m certainly not saying you have to allow your cat to pee in the sink! Here are some temporary steps to take to prevent cats from peeing in the tub, shower or sink while you work on getting them to use their litterbox again:

  • Don’t let the cat into the bathroom at all!
  • Keep a few inches of water in the tub/shower/sink when you’re not using them.
  • Remember how I mentioned cats have sensitive noses? Use this to your advantage by placing citrus air fresheners or soap with a strong perfume scent in the bathroom to repel your cat. 
  • Spread aluminum foil or plastic sheeting on the surface in question.
  • Try putting cat deterrent mats in the tub or shower 
  • Place “SSScat” compressed air with a motion sensor in the area 

How to Remove Cat Urine Odor from Sink or Bathtub

Cat pee stinks and most people don’t want that smell in their bathroom! You must also remove the cat urine odor from the tub/shower/sink to avoid attracting repeated urination there. Soap and water often aren’t enough to get rid of cat pee odor. Instead, try an enzymatic cleaner like Nature’s Miracle. Follow the directions on the label for the best results.

Avoid using household cleaners that contain ammonia as it may smell like urine and attract the cat to keep peeing there. 

Finally, keep the rest of the bathroom, particularly the toilet, spotless. While there is no scientific data to back this up, I occasionally wonder if cats prefer to pee in the bathroom because they can smell human pee there!


If your cat is peeing in the sink, don’t get frustrated! There are a few common reasons cats pee in the bathtub, shower, or sink. Bladder irritation is the first thing that comes to mind for a veterinarian. But your cat may be expressing normal behavior or could have a litterbox aversion that’s causing them to seek alternative toileting places. 

Once the underlying cause is identified, most cats can return to using their litterbox with a little help from you and their veterinarian.

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  1. Beaver, B. V., Terry, M. L., & LaSagna, C. L. (1989). Effectiveness of products in eliminating cat urine odors from carpet. Journal of the American Veterinary Medical Association, 194(11), 1589-1591.
  2. Guy, N. C., Hopson, M., & Vanderstichel, R. (2014). Litterbox size preference in domestic cats (Felis catus). Journal of Veterinary Behavior, 9(2), 78-82.
  3. Lekcharoensuk, C., Osborne, C. A., & Lulich, J. P. (2001). Epidemiologic study of risk factors for lower urinary tract diseases in cats. Journal of the American Veterinary Medical Association, 218(9), 1429-1435.
  4. Sung, W., & Crowell-Davis, S. L. (2006). Elimination behavior patterns of domestic cats (Felis catus) with and without elimination behavior problems. American journal of veterinary research, 67(9), 1500-1504.