Why Is My Cat Drinking So Much Water?

Cats can be surprisingly subtle when something is bothering them. However, a change in how much water your cat drinks can sometimes be one of the first clues that something is going on medically. While drinking more water after a particularly warm day or after eating more dry food can be perfectly normal, noticeable increased thirst can also point to an underlying health problem.

If your cat is drinking more water than usual, it can be something as simple as a change in your cat’s diet to medical conditions such as kidney disease, diabetes, or hyperthyroidism. First, it’s important to decipher what counts as excessive water drinking and knowing what other signs to watch for to decide if it’s time to call your veterinarian.

How Much Water Should a Cat Drink?

A cat's daily water needs depend on several factors, including body size, diet, activity level, and the temperature of their environment. As a general guideline, cats need roughly 3.5–4.5 ounces of water per 5 pounds of body weight each day from all sources, including the water contained in their food.

This means a 10-pound cat may need around 7–9 ounces of total water each day. A cat who eats wet food may actually drink relatively little from their water bowl because canned food contains a significant amount of moisture. Cats eating primarily dry food usually need to drink more directly from their water source.

Because of these differences, there isn't one specific amount that automatically means a cat is drinking too much. What matters most is a noticeable change from your cat's normal drinking habits.

How Can You Tell If Your Cat Is Drinking Too Much Water?

Because cats can drink from several places around the house, it isn't always easy to know exactly how much they're consuming. If you're concerned about your cat's water intake, try measuring how much water you put into their bowl over a 24-hour period and measuring what's left at the end of the day.

Also pay attention to how often you refill the bowl. If you have multiple cats, monitoring one cat's individual intake can be more difficult, so temporarily separating them during meals and providing separate water bowls can help.

Don't forget to consider water in your cat's food. A cat eating mostly wet food may naturally drink less from the bowl than a cat eating dry kibble.

Why Is My Cat Suddenly Drinking More Water?

A cat who suddenly starts visiting the water bowl much more frequently deserves some attention. Increased thirst, medically known as polydipsia, often occurs because the body is losing more water than usual or because something is affecting the way the kidneys regulate fluids.

Sometimes the reason is completely harmless. A switch from wet food to dry food, warmer weather, increased activity, or a saltier-than-usual diet can all make a cat drink more. However, persistent excessive thirst can be an important symptom of disease, particularly in middle-aged and senior cats.

Kidney Disease Can Cause Increased Thirst

Chronic kidney disease is one of the more common reasons older cats start drinking and urinating more. The kidneys normally filter waste from the blood while helping the body conserve water. As kidney function declines, the kidneys become less efficient at concentrating urine.

As a result, a cat with kidney disease may produce larger amounts of dilute urine and lose more water through urination. Your cat then drinks more to replace that lost fluid.

Increased thirst might appear before any other obvious signs of kidney disease, which makes changes in drinking and urination particularly important to notice. Other symptoms can include weight loss, decreased appetite, vomiting, lethargy, and a decline in your cat’s overall condition.

Feline Diabetes Can Make Cats Very Thirsty

Diabetes mellitus can also cause a cat to drink much more water than usual. With diabetes, the body either doesn't produce enough insulin or doesn't respond properly to insulin. This causes glucose to build up in the bloodstream.

When blood glucose levels become high enough, glucose spills into the urine. The glucose draws additional water into the urine, causing the cat to urinate more frequently and lose fluids. Increased thirst follows as the body attempts to compensate.

Some cats with diabetes also lose weight despite having a normal or increased appetite. Increased urination, increased hunger, weight loss, and excessive thirst together are important signs that you should see your veterinarian.

Hyperthyroidism May Increase Thirst

Hyperthyroidism is another condition that commonly affects older cats. The thyroid gland produces hormones that regulate metabolism, and an overactive thyroid can cause the body's metabolism to speed up.

Cats with hyperthyroidism may become unusually hungry while losing weight. They may also become restless, vocal, or more active than usual. Increased drinking and urination can occur as well.

Because many symptoms of hyperthyroidism overlap with other conditions common in senior cats, your veterinarian may recommend blood and urine testing to determine what is causing the change.

Urinary Problems Can Affect Drinking and Urination

Problems involving the urinary tract can sometimes make your cat’s drinking and urination seem different. A cat with bladder inflammation, a urinary tract infection, or another urinary condition may make more trips to the litter box.

However, there’s an important difference between urinating frequently and producing a large amount of urine. A cat with bladder irritation might repeatedly visit the litter box and only pass small amounts of urine. A cat with kidney disease or diabetes may produce much larger volumes of urine and drink more to replace the lost fluid.

If your cat is straining to urinate, crying in the litter box, repeatedly attempting to urinate, or producing little or no urine, don't wait to see whether the problem resolves. A urinary blockage can become a life-threatening emergency, particularly in male cats.

Your Cat's Diet Can Change How Much They Drink

Diet is one of the simplest explanations for a change in drinking habits. Wet cat food contains a large amount of water, while dry kibble contains considerably less moisture.

A cat who eats mostly canned food may barely touch their water bowl because they're getting much of their daily water from their meals. If you recently switched your cat to dry food, you may notice them drinking significantly more.

This doesn't necessarily mean anything is wrong. In fact, drinking more water can be a good thing when a cat eats dry food. What matters is whether the increase seems excessive or occurs alongside other changes in appetite, weight, urination, or behavior.

Hot Weather Can Make Cats Drink More

Just like people, cats may need more water when temperatures rise. Increased environmental heat can increase fluid loss and make your cat thirstier.

Your cat may also drink more after playing, exercising, or spending time in a warmer area of the home. If their increased drinking corresponds with hot weather and returns to normal when temperatures cool down, it generally doesn’t indicate a medical problem.

Still, persistent excessive thirst shouldn't automatically be blamed on the weather, especially in an older cat.

What Other Symptoms Should You Watch For?

Drinking more water becomes more concerning when it occurs with other changes in your cat's health or behavior. Keep an eye on the litter box as well as your cat's food bowl, since changes in thirst and urination often occur together.

Signs that may accompany excessive drinking include:

• Urinating more frequently or producing larger amounts of urine

• Urinating outside the litter box

• Increased appetite or unusual hunger

• Weight loss

• Decreased appetite

• Vomiting

• Diarrhea

• Lethargy or weakness

• Restlessness or increased vocalization

• Poor coat condition

• Dehydration

• Changes in behavior

• Difficulty or straining to urinate

When Should You Take Your Cat to the Vet?

A cat who drinks a little more water occasionally doesn't necessarily need an immediate veterinary visit. However, a noticeable and persistent change in thirst deserves attention, particularly if you cannot explain it by a diet change, hot weather, or increased activity.

It's especially important to schedule an appointment if your cat is drinking and urinating more while also losing weight, eating differently, vomiting, becoming less active, or acting unlike themselves. Senior cats deserve particular attention because kidney disease, diabetes, and hyperthyroidism become more common with age.

Your veterinarian will likely ask about your cat's diet, drinking habits, urination, appetite, weight, and any other changes you've noticed. Bloodwork and a urinalysis can provide your vet with valuable information about kidney function, blood glucose levels, thyroid health, hydration, and urinary problems.

Final Thoughts

If your cat is drinking more water, it can be something relatively simple, such as your cat is eating more dry food or dealing with warmer temperatures. But persistent excessive thirst can also be an early warning sign of kidney disease, diabetes, hyperthyroidism, or another medical condition.

Pay attention to changes in both drinking and urination, and look for other signs such as weight loss, increased hunger, vomiting, lethargy, or changes in litter box habits. When a cat's drinking habits change noticeably and stay that way, a veterinary checkup is the safest way to find out what's happening