Answer:
6 litres is highly inadvisable and dangerous
Step-by-step explanation:
The average human bladder can only hold between 400-600 ml, or .6 litres at maximum.
There is such thing as overhydration and it is dangerous. Please don't drink 6 litres of water all at once.
For instance, you should be drinking 3.7 litres in a whole day, WITH bathroom breaks. Please be safe.