How much water should a dog drink per day?

Most dogs drink roughly 50–60 ml per kg bodyweight daily — about 500–750 ml for a 10–15 kg dog. Drinking noticeably more than usual for several days warrants vet blood and urine tests.

Can hot weather make my dog drink more?

Yes — dogs drink more in warm weather and after exercise. A temporary increase after a hot walk is normal. Sustained excessive drinking over days needs investigation.

When is increased thirst an emergency?

Extreme lethargy, vomiting, collapse, or not eating alongside heavy drinking needs same-day care. Diabetic dogs can develop ketoacidosis — an emergency.

Dog Health

Why Is My Dog Drinking So Much Water UK?

Quick answer

**Sustained excessive drinking usually signals illness** — commonly [diabetes](/glossary/diabetes-mellitus), kidney disease, or [Cushing's disease](/glossary/cushings-disease). Measure intake over 24 hours if unsure. Book vet **blood tests and urinalysis** if your dog's bowl empties faster than usual for more than a few days — do not dismiss it as normal ageing.

Key takeaways

Increased thirst (polydipsia) commonly indicates diabetes mellitus, kidney disease, Cushing's disease, pyometra in unspayed females, or certain medications. Less often, liver disease or infection is involved.
Most dogs drink roughly 50–60 ml per kg bodyweight daily — about 500–750 ml for a 10–15 kg dog. Drinking noticeably more than usual for several days warrants vet blood and urine tests.
Yes — dogs drink more in warm weather and after exercise. A temporary increase after a hot walk is normal. Sustained excessive drinking over days needs investigation.

The full picture

Causes, home monitoring, treatment options and the exact signs that mean call your vet — in the complete guide.

Read the full guide Check symptoms

Frequently Asked Questions

Why is my dog drinking so much water?: Increased thirst (polydipsia) commonly indicates diabetes mellitus, kidney disease, Cushing's disease, pyometra in unspayed females, or certain medications. Less often, liver disease or infection is involved.
How much water should a dog drink per day?: Most dogs drink roughly 50–60 ml per kg bodyweight daily — about 500–750 ml for a 10–15 kg dog. Drinking noticeably more than usual for several days warrants vet blood and urine tests.
Can hot weather make my dog drink more?: Yes — dogs drink more in warm weather and after exercise. A temporary increase after a hot walk is normal. Sustained excessive drinking over days needs investigation.
When is increased thirst an emergency?: Extreme lethargy, vomiting, collapse, or not eating alongside heavy drinking needs same-day care. Diabetic dogs can develop ketoacidosis — an emergency.

Reviewed 2026-07-19 against UK veterinary guidance · Information only — not a substitute for seeing your vet.