A practical guide to tell mild from serious — but when in doubt, always ask your vet.
Last reviewed: 2026-09-05 · Reference ranges: ASPCA, Pet Poison Helpline & Merck Veterinary Manual
Veterinary advice recommended today — For most cases, follow the home-care steps below and call your vet the same day if warning signs appear.
Increased thirst in cats is a classic early clue for diabetes, kidney disease or an overactive thyroid. Any clear rise in drinking deserves a vet visit.
Contact your vet if any of these apply:
Never restrict water for a cat that drinks a lot. Measure daily intake and make a note of litter-box changes. Book a vet visit within a few days.
Your vet may run blood work, urine tests and possibly blood pressure checks to find the cause.
Roughly, dogs normally drink about 50–70 ml per kg per day and cats about 40–60 ml, but this varies with diet and weather. A sudden, clear and lasting increase is the real warning sign.
Increased thirst with house-soiling in older pets commonly points to kidney disease, diabetes or hormonal issues. Do not restrict water; book a vet visit to run blood and urine tests.
Same symptom in Dog: see Dog Drinking a Lot of Water — causes and home care can differ by species.
This page is educational triage information, not a diagnosis. Pets vary — when in doubt, ask your vet. In an emergency, contact your local emergency clinic or pet poison hotline directly.