umm, the time lapse is the important factor, which you left out.
it takes 30-60 days usually.
Too much water is not good for you.
from the internet:
Over-hydration and water intoxication happens when you drink more water than your kidneys can get rid of via urine.
But the amount of water isn't the only factor. How long you take to drink the water also counts.
You have a greater risk of developing water intoxication if you drink a lot of water in a short period of time. The risk is less if you drink the same amount over a much longer period of time.
Symptoms of hyponatremia can occur from as little as 0.8-1 gallons of water in a short amount of time.
Your kidneys can eliminate about 5.3-7.4 gallons of water a day, but they can't get rid of more than 27-33 ounces per hour. Therefore, in order to avoid hyponatremia symptoms, you should not drink more than 27-33 ounces of water per hour, on average.
Many reported cases of water intoxication result from drinking large amounts of water in a short period of time. For example, one report describes soldiers who developed symptoms after consuming half a gallon of water (1.8 liters or more) per hour. Another report shows the development of hyponatremia with water intake of 2.5-5.6 gallons, or 10-20 liters, in just a few hours.