Why does my dog drink so much water?

Your dog may be drinking a lot for a simple reason, or it may be a sign of illness.

Common harmless causes: hot weather, lots of exercise, switching to dry food, salty treats, or being a bit dehydrated after vomiting/diarrhea.

Medical causes to watch for: kidney disease, diabetes, Cushing’s disease, urinary tract infection, liver disease, or pyometra in unspayed females. Some medicines like prednisone, diuretics, and phenobarbital can also cause extra thirst.

See a vet soon if the drinking is new, constant, or comes with frequent urination, weight loss, vomiting, lethargy, or appetite changes.

A healthy dog usually drinks about 20–70 mL per kg per day. If it’s more like 90–100 mL per kg daily or higher, that’s excessive. Don’t restrict water; instead, schedule a vet check with urine and blood tests.