There is no fixed universal amount of water that triggers hyponatremia, as it depends on age, body weight, kidney function, and overall health. For a healthy adult, drinking more than 3 to 4 liters of water within a few hours can overwhelm the kidneys' ability to excrete excess fluid, diluting sodium levels in the blood. People with weaker kidney function, endurance athletes, or those who drink water extremely quickly may develop hyponatremia with even less intake, while rapid, excessive water consumption disrupts electrolyte balance and can lead to symptoms like nausea, headache, confusion, or in severe cases, seizures and organ damage.