Is Your Cat Drinking More Water? What It Can Mean

A cat drinking more water than usual can be a sign that something is wrong, so it's worth a vet visit. Kidney disease, diabetes and an overactive thyroid are common causes, and only your vet can tell which it is.

A sign, not a diagnosis

Vets call increased thirst polydipsia, and increased urination polyuria. PDSA says the two usually come together: the more a cat drinks, the more it needs to pee, and the reverse.

Cats get most of their fluid from food, especially wet food, so PDSA says it's common to see them drink only now and again. A cat that's suddenly at the bowl a lot is worth noticing.

With chronic kidney disease, the Merck Veterinary Manual says the earliest signs are usually excessive thirst and urination, though they don't begin to appear until Stage II or III.

Medical causes your vet will look for

International Cat Care names the most common causes as:

• Kidney disease
• Diabetes mellitus
• Hyperthyroidism (an overactive thyroid)
• High blood calcium

It mentions liver disease too, and PDSA adds urine infections, fever, and medicines that increase thirst, such as steroids.

You can't tell these apart at home. Cornell lists weight loss with a good appetite, plus more drinking and urinating, as common signs of both diabetes and hyperthyroidism.

Other reasons a cat drinks more

Diet matters. International Cat Care says a cat on wet food gets a large share of its water from food, while cats fed mainly dry food naturally drink more. It also says cats may drink more in warmer weather, or to make up for fluid lost after vomiting or diarrhea.

None of this rules out illness. And PDSA is clear: never withhold water from your cat.

Signs to look for

You may never catch your cat drinking, so look for other clues. PDSA lists:

• The water bowl emptying faster than usual
• Seeming thirsty all the time
• Drinking from places they usually don't, like taps, the toilet, sinks or the bath
• Drinking so much they vomit
• More litter box visits, or larger amounts of urine
• Peeing in the house

If you use clumping litter, watch the clumps. The American Association of Feline Practitioners lists "larger urine clumps" among the owner concerns vets weigh when diagnosing diabetes. Our guide to litter box changes covers the rest.

How much water should a cat drink?

The sources give a rough daily need, and lines for drinking too much that don't agree.

How much of that need comes from the bowl depends on diet: Cornell and VCA each say cats on wet or canned food may drink less. Cornell's line is the lower of the two. A number under either isn't an all-clear: International Cat Care says any cat drinking more than usual should be seen by a vet.

How to measure it at home

International Cat Care's 24-hour check: fill the water bowls to the brim, measure what's left after 24 hours, and take that away from the full amount. A measuring cup helps, and if you top a bowl up, measure what you add. Write down the result, the date, and what your cat ate.

If other pets share the bowls, International Cat Care suggests keeping them apart for the day, but only if that doesn't distress them. The threshold is per kilogram, so a recent weight helps: see how often to weigh your cat.

When it can't wait

PDSA's advice is to contact your vet for an appointment. Some signs need faster help:

• Little or no urine, small clumps, or straining in the box. VCA says to seek immediate veterinary attention, and calls lack of urination a life-threatening emergency.
• Not eating for more than 24 hours. VCA says to seek immediate veterinary attention.
• More thirst with lethargy, weakness, eating less, or trouble breathing. Merck lists these as signs of diabetic ketoacidosis, an emergency complication of untreated or poorly treated diabetes, and says a cat with them should be seen right away.

What to bring to the vet

VCA says your cat's history can give clues to the cause, and that measuring 24-hour intake helps your vet judge how severe the problem is. Bring:

• The date you first noticed the change
• Your 24-hour measurements
• Litter box changes: more trips, bigger clumps, accidents
• Appetite, and any vomiting or diarrhea
• Recent weights
• Every medicine and supplement your cat takes
• A urine sample if you can. PDSA suggests one, and International Cat Care explains how to collect it.

A cat journal gives your vet dates instead of guesses. Tamadoggo has no water counter, but in its cat journal app a dated Health Episode or General Note entry can hold each measurement, and Weight Checks chart your cat's weight over time.

Sources

• Increased thirst and drinking, International Cat Care
• Encouraging your cat to drink: a guide for caregivers, International Cat Care
• Chronic kidney disease (CKD) in cats, International Cat Care
• Is my cat drinking and weeing too much?, PDSA
• Testing for Increased Thirst and Urination, VCA Animal Hospitals
• Recognizing the Signs of Illness in Cats, VCA Animal Hospitals
• How To Get Your Cat To Drink More Water, VCA Animal Hospitals
• The Special Needs of the Senior Cat, Cornell Feline Health Center
• Hydration, Cornell Feline Health Center
• Feline Diabetes, Cornell Feline Health Center
• Hyperthyroidism in Cats, Cornell Feline Health Center
• Chronic Kidney Disease, Cornell Feline Health Center
• Noninfectious Diseases of the Urinary System of Cats, Merck Veterinary Manual
• Disorders of the Pancreas in Cats, Merck Veterinary Manual
• Diabetes Toolkit: Diagnosis, American Association of Feline Practitioners
• Infectious Diseases of the Urinary System of Cats, Merck Veterinary Manual