Excessive Thirst in Cats — Symptom Assessment Guide
A practical guide to increased drinking (polydipsia) in cats: what it looks like, likely causes (CKD, diabetes, hyperthyroidism), home checks, decision tree, and when to see a vet.
Quick Assessment
- Is this an emergency? No — not usually. Yes — if your cat is very lethargic, vomiting repeatedly, having seizures, collapsing, or not urinating.
- Most common causes: chronic kidney disease (CKD), diabetes mellitus, hyperthyroidism.
- When to see a vet: if increased drinking lasts more than 48–72 hours, is accompanied by increased urination, weight loss, appetite changes, vomiting, or changes in behavior.
What
Frequently Asked Questions
How much water is normal for a cat?
Most adult cats drink roughly 40–60 mL/kg/day (about 200–300 mL/day for a typical 4–5 kg cat) but this varies with diet (wet vs dry), temperature, and activity. Use your cat's usual intake as the baseline.
When does increased thirst become urgent?
Urgent if your cat is weak, very sleepy, vomiting repeatedly, having trouble breathing, unresponsive, seizing, or not producing urine. Otherwise, see your vet within 48–72 hours if the increase persists.
Will my vet need blood tests?
Yes. Polydipsia in cats almost always warrants blood work and a urinalysis to check kidney function (BUN, creatinine, SDMA), blood glucose, and thyroid levels (T4), plus electrolytes and urine concentration.
References & Citations
Parts of this article reference data from Merck Veterinary Manual.