Does Dry Food Dehydrate Cats?


As fluffy felines, cats are often assumed to get the hydration they need from their food alone. However, water is a crucial nutrient for cats. Without adequate water intake, cats can quickly become dehydrated, leading to serious health complications.

But do cats that eat only dry food get the hydration they need? How does a dry diet impact feline hydration levels? What are the signs of dehydration cat owners should look out for? This article will dive into these questions, shedding light on hydration requirements for our furry friends.

Background on Cats’ Hydration Needs

Cats evolved as desert animals and have a relatively low thirst drive compared to other domestic pets like dogs. In the wild, cats obtained most of their moisture needs from the prey they consumed rather than drinking water directly. As a result, cats do not have a strong natural instinct to drink water regularly throughout the day.

According to Cornell University College of Veterinary Medicine, cats need to consume about 4 ounces of water per 5 pounds of lean body weight per day. So the average 10-pound cat should drink about 1 cup of water per day to stay properly hydrated. However, many cats do not naturally drink this much water on their own.1

Since cats evolved in very dry environments and got most of their moisture from prey, they developed a low thirst drive and may not recognize early signs of dehydration. This makes cats susceptible to dehydration, especially when fed dry food diets.2

Dry Food vs Wet Food

Dry cat food and wet cat food have some significant differences when it comes to their moisture content and hydrating abilities. Dry food contains around 6-10% moisture whereas wet food contains approximately 70-78% moisture (DailyPaws). The high moisture content of wet food can help cats stay hydrated, while the low moisture content of dry food may contribute to dehydration.

Cats have a low thirst drive and do not drink as much water as they need, relying on food for a majority of their moisture intake. Dry food’s lower moisture content means cats eating only dry food often do not get enough water. Canned wet food has high moisture and can provide most or all of a cat’s needed daily water, helping prevent dehydration (PetMD).

Feeding only dry food can put cats at risk of mild chronic dehydration. While mixing wet and dry food or providing extra water can help, wet food’s high moisture content makes it the best option for meeting cats’ hydration needs.

Signs of Dehydration in Cats

There are several telltale signs that your cat may be dehydrated. According to PetMD, the most obvious symptom is lethargy and weakness (1). Dehydrated cats often lack energy and may have difficulty standing or walking. Other common symptoms include dry or tacky gums when you lift your cat’s lips and gently press on their gums (2). Normally a cat’s gums should be moist or slimy. Dry, sticky gums indicate a lack of hydration. You may also notice sunken eyes or skin that stays tenting after being pinched and released. Vomiting, urinating less frequently, increased heart rate, and rapid breathing can also signal dehydration in cats.

Dangers of Dehydration

Dehydration can be extremely dangerous for cats if left untreated. According to the Cornell University College of Veterinary Medicine, dehydration can lead to potentially life-threatening problems such as kidney disease, electrolyte abnormalities, constipation, and poor skin elasticity. Severe dehydration requires immediate veterinary treatment with intravenous fluids to restore hydration and electrolyte balance.

Mild to moderate dehydration can also cause other health issues over time. According to WebMD, chronic low-level dehydration stresses the kidneys and can predispose cats to kidney disease later in life. Dehydration also decreases blood volume which reduces oxygen delivery to tissues and organs. This can negatively impact your cat’s overall health and quality of life.

That’s why it’s so important to monitor your cat for signs of dehydration and take steps to increase their fluid intake if needed. Left untreated, dehydration places cats at risk for serious complications.

Tips to Keep Cats Hydrated

There are several ways to help ensure cats get enough hydration throughout the day:

Feeding wet food is an easy way to increase water intake. Canned food contains up to 75% water, versus only 10% for dry food. Feeding all or half of the daily calories from wet food can dramatically increase overall water consumption (Source).

Using a cat fountain provides a steady supply of fresh, flowing water that encourages drinking. Cats prefer running water and will drink more when it’s constantly circulating and filtered (Source).

Adding extra water to dry food can make it more appetizing and hydrating. Mixing in a few tablespoons of water helps increase moisture content without sacrificing the benefits of dry kibble (Source).

How Much Water Do Cats Need?

According to veterinary guidelines, the daily recommended water intake for cats is around 4-6 ounces (1/2 – 3/4 cup) per 5 pounds of body weight (1). This means a 10 pound cat needs about 8-12 ounces or 1-1.5 cups of water per day. To calculate your cat’s ideal daily water intake, take their weight in pounds and multiply by 4-6 ounces per 5 pounds.

So for example, if your cat weighs 15 pounds, multiply 15 by 4 ounces per 5 pounds, which equals 12 ounces or 1.5 cups per day. Or multiply 15 pounds by 6 ounces per 5 pounds, which is 18 ounces or 2.25 cups per day. Therefore, the daily recommended water intake for a 15 pound cat is 1.5-2.25 cups.

It’s important to provide fresh, clean drinking water for your cat at all times. Measure out their expected daily water intake to get a sense of how much they should be drinking. If your cat is not meeting their daily recommendations, there may be an issue with dehydration that needs to be addressed (1). Monitoring water intake is one way to stay on top of your cat’s hydration status.

Ask Your Vet

It is very important to consult your vet if you feel your cat may be dehydrated or is at risk of becoming dehydrated. A veterinarian can diagnose and properly assess dehydration in cats by performing tests like evaluating the hydration status of the skin, checking capillary refill time, taking the cat’s temperature, and doing bloodwork to check things like packed cell volume.

Your vet can provide guidance on the best ways to encourage hydration for your individual cat and give recommendations on food, water intake, and supplements as needed. They may suggest providing subcutaneous fluids to treat dehydration or prevent it in an at-risk cat. Severe dehydration can lead to kidney failure, electrolyte imbalances, and even death so it is crucial to seek veterinary care. Contact your vet promptly if your cat is showing any signs of dehydration like lethargy, dry gums, sunken eyes, not eating or drinking, etc.

Regular vet checkups can help monitor your cat’s hydration status over time. Establishing a relationship with a vet you trust regarding your cat’s health and hydration needs is highly recommended. Don’t hesitate to ask your vet questions about optimizing hydration and preventing dehydration for your cat’s unique situation.

The Bottom Line

In summary, while dry food can be part of a healthy feline diet, relying solely on kibble puts cats at risk for dehydration. Dry food has very little moisture content compared to a cat’s natural diet. As obligate carnivores, cats get most of their water from their prey in the wild. Domestic cats have a low thirst drive, so they often do not drink enough water to make up for the lack of moisture in dry food.[1] Signs of dehydration include lethargy, dry gums and nose, sunken eyes, and urinating less frequently. Severe dehydration can lead to kidney disease and other serious health issues.

Experts recommend mixing some wet/canned food into a cat’s diet, or adding extra water to dry food to increase moisture intake. Cats should have fresh, clean water available at all times. Additionally, cat owners can monitor litter box habits, offer cat-safe broths or fountain waterers, and consult a veterinarian to ensure their cat is properly hydrated. While dry food does not inherently dehydrate cats if they drink enough water, relying solely on kibble increases dehydration risks compared to a diet with adequate moisture from wet food or added water.


[1] Little, Susan, DVM. “Water for Your Cat: The Fountain of Youth.” The Spruce Pets, 2022, Accessed 12 Jan 2023.

[2] Pitcairn, Richard H., and Susan Hubble Pitcairn. Dr. Pitcairn’s Complete Guide to Natural Health for Dogs & Cats. Rodale, 2005.

[3] Rucinsky, Renee, et al. “AAFP 2006 Feline Zoonoses Guidelines.” Journal of Feline Medicine and Surgery, vol. 12, no. 1, 2010, pp. 43–65.,

[4] Little, Susan. “How Much Water Does a Cat Need?” The Spruce Pets, 2019, Accessed 12 Jan 2023.

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