If you've noticed your cat drinking more water than usual — hovering over the bowl, seeking out faucets, or draining their dish faster than normal — it's worth paying attention. Increased thirst in cats (called polydipsia) is one of the most common early signs of several serious conditions.
How Much Water Is Normal?
A healthy cat typically drinks about 3.5 to 4.5 ounces of water per 5 pounds of body weight per day. For a 10-lb cat, that's roughly 7 to 9 ounces daily.
Cats on wet food diets naturally drink less because they get moisture from their food. Cats on dry kibble drink more. A sudden increase beyond their usual pattern is what matters — not hitting an exact number.
Common Causes of Excessive Drinking
When a cat starts drinking noticeably more, these are the conditions vets check for first:
- Chronic kidney disease (CKD) — The most common cause in older cats. As kidneys lose function, they can't concentrate urine properly, so the cat drinks more to compensate. CKD is progressive but manageable when caught early.
- Diabetes mellitus — Just like in humans, diabetic cats have elevated blood sugar and drink more to flush the excess. You'll often see increased urination and weight loss alongside the thirst.
- Hyperthyroidism — An overactive thyroid (very common in senior cats) revs up the metabolism, causing increased thirst, hunger, weight loss, and restlessness.
- Urinary tract infection (UTI) — Infections can increase thirst and cause frequent, painful urination. More common in female cats but possible in any cat.
- Liver disease — Less common but worth checking, especially if other symptoms are present.
- Medications — Some drugs (steroids, certain diuretics) increase thirst as a side effect.
How to Tell If It's Excessive
- Watch the water bowl — Mark the water level and check how much drops in 24 hours.
- Count litter box clumps — More clumps or larger clumps than usual means more urination, which goes hand-in-hand with increased drinking.
- Note behavioral changes — Is your cat seeking water from unusual sources (faucets, toilets, plant saucers)? That's a sign they're thirstier than their bowl can satisfy.
- Weigh them — Unexplained weight loss combined with increased drinking is a strong signal for diabetes or hyperthyroidism.
When to See the Vet
Don't wait on this one. Increased thirst that lasts more than a day or two warrants a vet visit. The conditions that cause polydipsia in cats are all more treatable when caught early.
Your vet will likely run:
- Blood panel (kidney values, blood sugar, thyroid levels)
- Urinalysis (concentration, infection, glucose)
- Possibly an ultrasound for kidney assessment
These tests are straightforward and can give answers quickly.
What You Can Do Now
Keep fresh water available at all times. Track intake for a few days so you have data to share with your vet. And don't restrict water — if your cat is drinking more, their body needs it.
If your cat's drinking habits have changed and you want to understand what it might mean, Mylo can connect you with answers from veterinary sources and other cat owners who've navigated the same symptoms.