This report is about a Taiwanese woman who drank 7 litres of water a day - 3 times more than than recommended amount - in the hope of decreasing her blood pressure.
In short, the article tells us that drinking too much water on a constant basis can lead to hyponatremia, a condition where there is insufficient sodium in your blood, resulting in loss of sight or blindness.
So while it is good to drink lots of water, do not overdrink.