How many of us have heard that we are dehydrated and we need to drink at least eight glasses of water a day? I know that was what I have been exposed to. More refined versions include one quart of water for every 50 pounds of body weight so that would increase it to 12 to 16 glasses a day for most of us. This is what I recommended at one time but after awhile it never made much sense to me so I refined my recommendations to look at your urine. As long as you were not taking riboflavin (vitamin B-2) which fluoresces and turns your urine bright yellow (it is also in most multi-vitamins) then your urine should be a very light colored yellow. If it is a deep yellow then you are likely not drinking enough water.
So I was delighted to read in my Family Practice Newspaper last night that the Institute of Medicine Panel actually reached the same rational conclusion. They rejected the conventional wisdom that people need to drink eight glasses of water a day and concluded that on a daily basis people get adequate amounts of water from normal drinking behavior--consumption of beverages at meals and in other social situations--and by letting their thirst guide them.
If this is a topic that interests you then you will want to review the 500-page report that I link to below. Please remember though that the quality of water is an important consideration to the quantity. So you will want to avoid distilled water and also fluoridated water by getting a good filter. You really want to avoid bottled water unless it is absolutely necessary as it is a strain on the environment. Please also remember to avoid storing your water in typical Nalgene bottles as they can leach an unsafe chemical called BPA. I recently switched to the high-density polyethelene (HDPE) Nalgene to store my water when I go on trips.
Family Practice News April 2004
National Academic Press Free Full-Text 500-page article