Why Does My Cat’s Litter Box Smell Like Ammonia?

Why Does My Cat's Litter Box Smell Like Ammonia?

Cats make excellent additions to the majority of households, but I must admit they can also pose a number of challenges too, with these ranging from the behavioural to the more logistical. One particular aspect of cat ownership that sometimes takes people by surprise is the effort involved in managing their toilet habits, as well as the odours that are produced. In particular, the smell of ammonia is a common and unpleasant issue, worthy of your attention.

Why Does My Cat’s Litter Box Smell Like Ammonia? The simple explanation is that all cat urine contains ammonia in small amounts. Cat litter trays work by absorbing and drying out urine and this, in turn, leaves more concentrated ammonia behind, causing the smell. This smell can occur even in cat litter boxes with odour neutralising qualities and is worse if the urine is left for a long time, or if your cat is dehydrated.

The smell of ammonia within urine can also be indicative of health concerns, including infections and diseases. Below, I will also offer some additional information about why cat urine produces the ammonia smell, the steps you can take to minimise the odour, and the reasons why some cat litter can actually seem to exacerbate the problem.

Understanding the Smell of Ammonia

The smell of ammonia stemming from a litter box is a common complaint from cat owners, but few understand the reasons for the smell. Essentially, cat urine contains urea, which is an organic compound used to rid the body of amino acids. In the presence of oxygen, moisture and warmth, the urea breaks apart and becomes ammonia. It is worth pointing out that the amount of ammonia in a cat’s urine is actually fairly small, making it mostly harmless.

At this stage, if you are experiencing a particularly strong smell of ammonia originating from your cat’s litter box, you are likely wondering if this is indicative of something bad. The answer to that is: probably not. The reason why your cat’s urine produces such a strong smell of ammonia is usually a lot more simple. As the urine dries out, the compounds that are left behind – urea, ketones, and proteins – are more concentrated, or less diluted.

Cat litter boxes contribute directly to this problem because they are intentionally designed to dry urine out. They absorb moisture, in order to prevent urine from pooling. Yet, over time, this can result in a strong smell of ammonia. Indeed, it is usually the case that urine left in a cat litter tray for a while will smell worse than fresh cat urine left on less absorbent surfaces, even if the litter filler has odour control properties.

This explains why many cat owners believe the smell of ammonia is actually originating from the cat litter box itself, rather than from the urine. As I will cover in greater detail later on, different cat litter fillers can also influence the strength of the smell, which can also lead to cat owners thinking new litter filler is the root cause of the smell. Nevertheless, if cat urine is left to dry on any surface, it is likely to produce the same ammonia smell.

One of the single biggest factors influencing the potency of the smell is hydration. A cat which has taken in plenty of fluids will generally produce a more diluted urine, which has less of a smell, even after it dries out. It is also worth noting that the smell of ammonia within cat urine is also influenced by hormones – at least to some extent. This is why the smell is stronger in urine from cats that have not been spayed or neutered than in urine from ‘fixed’ cats.

Why Cat Litter Can Change the Smell

Some people do not actually notice the smell of ammonia within their cat’s urine until after they change the cat litter box filler they use. As a result of this, it is common for cat owners to mistakenly believe the smell is coming from the cat litter box itself, rather than from the urine. With that being said, while the cat litter is not responsible for the smell, the type of cat litter filler you use can have an impact on the potency of the smell.

Most cat litter box filler is made from either bentonite clay, silica gel or Fuller’s earth, and all of these are used because they have absorbent qualities, helping to draw moisture out of cat urine. This avoids the problem of having puddles of urine in your cat’s litter box and makes it significantly easier to clean up. However, as previously stated, the ammonia smell from cat urine becomes significantly stronger as the urine dries out.

In addition to this, different cat litter box fillers have different properties when it comes to fighting bacteria and controlling odours. Bacteria within the urine can grow rapidly in cat litter trays, and this can add to the smell. Meanwhile, some cat litter fillers focus more on odour control than the root cause. Changing cat litter can, therefore, result in the smell appearing stronger or weaker. Crucially, this does not mean the litter itself is giving off the odour.

Generally, the best approach is to try different cat litter fillers and see which one provides the best odour control for your cat. If you change filler and notice more of a smell, it may be worth changing back. Alternatively, you could try another brand, which uses a different substance, with different properties.

How to Minimise the Smell of Ammonia

The smell of ammonia from a cat’s litter box can be extremely unpleasant. Yet, for some people, it can actually go beyond that. When the smell is especially potent, it can trigger headaches in humans, and in people who are highly sensitive to the smell, it can even lead to symptoms more typically associated with asthma or allergies. For this reason, it is important to take steps to minimise the smell and the harm or disruption it causes.

In terms of what can be done, the single most effective step I can recommend is to try to clean the cat litter box as regularly as possible, reducing the amount of time cat urine is left to sit in the box and dry out. Furthermore, you should ensure that your cat has plenty to drink and that it is actually drinking properly. Things that may contribute to poor hydration habits among felines include stress, disruption to normal order, and new pets in the home.

When it comes to selecting your cat litter, there are no real benefits to selecting a less absorbent material, as this will simply lead to urine pooling in the litter box instead. Therefore, it is best to try to find a litter filler that absorbs urine and does something to combat the ammonia smell too. In particular, it is worth investing in a litter filler that includes anti-bacterial qualities and provides high-quality odour control.

The vast majority of litter filler types have their pros and cons. However, if controlling the ammonia smell is a major concern for you, I would personally recommend using silica gel litter. Not only can this keep the ammonia smell at bay for longer than most clay litters, some silica gel products even change colour to indicate the presence of potential problems with the urine, such as urinary tract infections or bladder stones.

Further Information About Cat Urine

Although usually nothing to worry about, the smell of ammonia within your cat’s litter box can sometimes be indicative of dehydration and illness, especially if it is unusually strong, or if it has become more noticeable without any other changes to the litter box itself. Moreover, your cat’s urine can also tell you a lot more besides, so it is important to be aware of it generally and to pay careful attention if you notice any major changes.

Healthy cat urine is typically a clear, pale yellow colour. While the strength of the colour can vary, depending on levels of hydration, cloudy urine is considered abnormal and can be indicative of a bladder condition. The urine should also not be completely clear. Some cat owners mistakenly think clear urine is a sign of optimum hydration, but in reality, it can be indicative of serious issues, like diabetes and kidney disease.

Other warning signs to look out for when checking your cat’s urine include sudden changes to the smell and the presence of blood. Additionally, there are certain behavioural changes to be aware of, such as your cat suddenly failing to urinate in their litter box, or your cat urinating much more frequently than normal. These various signs can suggest a number of different health issues, including urine infections, blood clots and even tumours.

It is critical that you seek veterinary advice as soon as possible upon noticing any of these abnormalities within your cat’s urine. Try not to panic, as some of these issues also have more harmless explanations, but it is better safe than sorry. Keep in mind that, with many of the most serious conditions, early detection and treatment can be vital.

Barbara Read

Barbara Read - Cat owner, researcher and behavioural expert. Cats are not only fantastic pets but also wonderful and complex animals with great personalities. It takes time and effort to learn their behaviour but its completely worth it.

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