January 14, 2025, 4:20 pm | Read time: 8 minutes
If your cat pees on the carpet or sofa, the smell can quickly become unbearable. PETBOOK editor and cat behavior expert Saskia Schneider explains how to properly remove cat urine and the reasons that can cause cats to become unclean.
Cats are known for their cleanliness and consistent use of their litter boxes. But what can you do if your feline friend urinates on the carpet, bed, or couch? The strong smell of cat urine poses a challenge for many, as conventional cleaners often don’t help. This is because the special composition of cat urine makes it particularly intense and long-lasting. In addition to the right approach to cleaning, it is crucial to understand the reasons for the cat’s behavior in order to find a long-term solution.
Overview
Why Does Cat Urine Smell So Bad?
Cats are territorial animals. They mark their territory not only visually but also olfactorily, i.e., by smell. To do this, they use feces, but above all, urine. This consists of substances such as
- urea
- creatine
- uric acid
- salts, such as sodium chloride
- electrolytes
Cats also have a special protein in their urine known as felinin. This protein remains on surfaces for an extremely long time and is not worn away by rain, sunlight, or other weather conditions. This makes sense for the cats, as their territory markings remain intact for a long time.
However, felinine does not cause the stench that we humans – or rather our noses – have to deal with. This comes mainly from urea (also called urea). When freshly excreted, it is almost odorless. It is only when bacteria break it down that ammonia is produced, which causes the pungent smell of urine. If urea is broken down further, thiols are also produced. These are odor-intensive substances that have a sulfur compound and are found in the defensive scent of skunks, for example.
Why Do Cats Urinate Outside Their Litter Box?
It is almost more important than removing cat urine to clarify the reason why it is being deposited outside their litter box. This is the only way to achieve long-term success. There are basically two reasons why cats urinate outside the litter box: physical or psychological.
Physical Problems
Often, a medical condition is the reason cats urinate outside the litter box. This can be urinary stones, for example, but also arthritis. These cause pain when going to the toilet, which the cat then associates with the place itself. If this inappropriate elimination occurs quite suddenly, it’s important to visit the veterinarian immediately.
Another reason may be that the cat does not like the litter. For example, because it hurts their paws or is unpleasant. In this case, it can often be observed that the animals choose “softer” places to do their business, such as the bath mat.
Psychological Causes
If a cat feels insecure in its territory, this often manifests itself in marking or urinating. There can be various reasons for this insecurity. It is often triggered by unfamiliar cats in the neighborhood that walk through the garden and leave scent marks. Urine stains are then mainly found near windows or the patio door.
Other cats in the household can also cause insecurity, for example, by bullying the animal or fighting over resources. Therefore, it’s essential to ensure you provide enough litter boxes. The golden rule here is: Number of cats plus one. Thus, for two cats, you would need three litter boxes.
There are many other reasons why cats become unclean. Basically, this behavior should always be taken seriously. If the vet can rule out health problems, you should seek help from a cat behavior consultant if necessary, as there is often a behavioral problem behind it.
Finding Cat Urine with a Black Light
The first step in successfully removing cat urine is to find all traces of urine. We often only discover fresh traces. If the urine has dried up, we can still smell it but not necessarily locate it. This is where black light helps.
Black light consists mainly of light in the UV spectrum. This is invisible to humans, but one of its properties is to make urine crystals fluoresce yellow.
It is best to wait until it is dark. Then, walk through the house with a black light flashlight. This not only shows where the urine is but also how old the stain is. While fresh urine fluoresces orange, old stains appear lighter. A white stain often indicates that there was once urine here. Although the urea has been successfully removed, it has attacked the material. 1
Why Household Remedies Are Often Not Enough to Remove Cat Urine
Home remedies or commercially available cleaners are usually recommended to remove cat urine. Practical tips include, for example, combinations of vinegar, bleach, and baking soda. Although these agents are quite successful in cleaning, they are not chemically able to completely remove all components of cat urine.
Therefore, it is important to use a cleaner that can break down the urea – the main cause of the pungent odor. Agents such as soap, vinegar, baking soda, chlorine, or bleach may temporarily remove the urine odor, but often, residues of urea remain, which can penetrate even deeper into carpets or upholstery during cleaning.
Should the urea come into contact with moisture again, the stain will begin to emit an odor once more. This is not always noticeable to us humans. However, the smell can encourage cats to urinate outside the toilet again.
How to Effectively Remove Cat Urine and Its Odor
To remove cat urine completely, you need to use special enzyme cleaners. Only these are able to completely break down the urea and thus prevent the typical urine odor from developing. 2
However, these cleaners work slightly differently from the typical vinegar and baking powder mix. To allow the enzymes to do their work, proceed as follows when removing cat urine:
- Soak up as much liquid as possible from the stain – using a paper towel, for example.
- Soak the affected area with sufficient enzyme cleaner.
- Leave the cleaner to work for 10 to 15 minutes so that the enzymes have enough time to break down the urea.
- Remove as much liquid as possible and allow the area to air dry.
Ideally, cover the “accident site” with something. On the one hand, to prevent the cat from doing its business there again straight away. Secondly, so that no one steps in the wet spot while the enzymes are doing their work.
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Removing Cat Urine From Furniture and Mattresses
It is particularly difficult to remove cat urine from furniture or mattresses, as the liquid often penetrates deep into the fabric. Enzyme cleaner is also the best option here. A sufficient amount should be applied to the stain to ensure that all the urea is reached and completely broken down by the enzymes.
It is best to soak up a large amount of liquid with several towels. To avoid having to sleep on the sofa until the mattress is completely dry, you can also place a layer of towels between the mattress and the sheets. Replace these daily, as it can usually take a few days for the stain to dry completely.
Sometimes, cat urine that has remained undetected for a long time has already soaked deep into the carpet or wood. In this case, there is often no other option but to remove the material. It is, therefore, best to prevent the cat from doing its business outside the litter box from the outset.
Important: Always remember that cats do not pee out of protest! Urinating outside a litter box is always a sign of discomfort, pain, or fear. Therefore, you should not only make an effort to remove the cat’s urine but also to find the cause. A happy cat is one that maintains cleanliness.
About the author: Dr. Saskia Schneider has a doctorate in biology. During her studies at Freie Universität Berlin, she specialized in zoology and animal behavior. In addition to her training as an editor, she trained as a behavioral consultant specializing in cats.
My Experience
“My cat Archie unfortunately urinated on my couch before he was neutered at the point where the two parts of the couch are joined together, of all places. The urine penetrated deep into the gap, which made cleaning difficult. I therefore borrowed a wet vacuum cleaner with a high-pressure cleaner function. I added enzyme cleaner to the tank, and the high-pressure function allowed it to penetrate the couch fabric deeply and work effectively. That really saved my couch.”