There was a big hoo haa quite a while ago about having too much water on a VLCD... as I think a lady died when she was on LL - however - she did drink like 4 litres of water in a couple of hours!
I would personally just stick to what you feel comfortable with (obviously keeping to the minimum amount required for CD) as each persons needs for water will be different according to height/ weight etc.Plus, each day is different too, sometimes you can take on more or less water.
Too much water is what killed Leah Betts, famously.
Even if you don't drink it quickly and poison your system, too much water can over-dilute essential minerals and salts in your system. Cambridge say anywhere from 2.2litres to twice that is fine, but more than twice that isn't advised.
In 2008, Jacqueline Henson, a 40-year-old British woman, died after drinking four liters of water in under two hours as part of her LighterLife diet plan.
Water poisoning is caused by excessive consumption of water during a short period of time. This leads to a disruption in normal brain function due to the imbalance of electrolytes in the body’s fluids. Humans are made up of approximately 55 to 65% water, depending on gender, so water is necessary to survive. Water in and of itself is not toxic by any means, but rapid ingestion of a large quantity of water can dilute the careful balance of sodium compounds in the body fluids.
Our body has a balanced method of processing and excreting fluids, either through urine or perspiration. Over-diluting the sodium and potassium levels in the blood plasma through excessive consumption of water is called hyponatremia and contributes to what is called an osmotic shift of the fluid inside and outside the cells. The pressure from this action results in a swelling of the cells, often in the central nervous system, including the brain. This may result in water intoxication, which is not as serious as water poisoning, or as it is also called, hyperhydration.
When the cell membranes can no longer withstand the pressure, the cells can begin to die. This is indicated in more serious forms of water intoxication and water poisoning. Symptoms of water poisoning include lightheadedness, vomiting, headache, nausea and unresponsiveness. When the sodium in the blood plasma falls to dangerous levels, swelling of the brain, coma, seizures and possibly death may occur.