Several age-related changes increase dehydration risk: diminished thirst sensation, decreased kidney function, lower total body water percentage, medications that increase fluid loss (diuretics), and reduced mobility that makes accessing water harder. Proactive hydration is essential.

Most seniors should aim for at least 6-8 cups (1.5-2 liters) of fluids daily, though individual needs vary based on weight, medications, and health conditions. Some medical conditions may require fluid restriction — always follow a doctor's specific guidance.

Watch for dark urine, dry mouth, confusion or increased disorientation, dizziness upon standing, constipation, decreased urine output, and sunken eyes. In seniors, confusion is often the first noticeable sign and is frequently mistaken for cognitive decline rather than dehydration.