In senior dogs, increased drinking most often traces back to a few high-probability differentials:
• Chronic kidney disease (CKD): As kidney tissue is lost, the kidneys struggle to concentrate urine, leading to increased urination and compensatory thirst. You may also see decreased appetite, weight loss, nausea, or bad breath.
• Diabetes mellitus: High blood glucose spills into urine and pulls water with it, causing marked urination and thirst. Hallmarks include increased appetite with weight loss, lethargy, and sometimes recurrent infections.
• Cushing’s disease (hyperadrenocorticism): Excess cortisol interferes with water balance and can cause increased thirst/urination, panting, pot-bellied appearance, muscle loss, thin skin, and recurrent skin or ear infections.
• Urinary tract infection (UTI): Seniors can develop UTIs that cause frequent urination, urgency, accidents, blood in urine, or discomfort—sometimes with increased drinking.
Because these conditions overlap in outward signs, veterinarians typically start with urinalysis and bloodwork to assess kidney values, glucose, electrolytes, and infection indicators, then add targeted testing (such as urine culture or endocrine testing) based on results and exam findings.