Excess fluid accumulation in the brain is called cerebral edema, which can affect the brain stem and cause central nervous system dysfunction. In severe cases, water intoxication can cause seizures, brain damage, coma and even death (1). Bottom line: Drinking too much water increases pressure inside the skull.Click to see full answer. Thereof, what happens to your kidneys when you drink too much water?Although uncommon, it’s possible to drink too much water. When your kidneys can’t excrete the excess water, the sodium content of your blood is diluted (hyponatremia) — which can be life-threatening. In general, though, drinking too much water is rare in healthy adults who eat an average American diet.Secondly, how much is too much water in a day? Your kidneys can eliminate about 5.3-7.4 gallons (20-28 liters) of water a day, but they can’t get rid of more than 27-33 ounces (0.8-1.0 liters) per hour (14, 15). Therefore, in order to avoid hyponatremia symptoms, you should not drink more than 27-33 ounces (0.8-1.0 liters) of water per hour, on average (14). Just so, how do I know if I drank too much water? You have throbbing headaches throughout the day Headaches are both a sign of overhydration and dehydration, similar to nausea, vomiting, and diarrhea. When you drink too much water, the salt concentration in your blood reduces, causing the cells in the organs throughout your body to swell.Can drinking too much water affect your liver?The result is too much water and not enough sodium. Thus, overhydration generally results in low sodium levels in the blood (hyponatremia), which can be dangerous. However, drinking large amounts of water usually does not cause overhydration if the pituitary gland, kidneys, liver, and heart are functioning normally.