A good rule of thumb I was given to determine if I am drinking enough water is to check urine color. If your urine is dark yellow (vitamins can cause this too...so use your noggin! ) you might need more water. Urine should be pale in color if you are properly hydrated.

i could never go by the dark urine rule,the vitamins i take makes it very dark yellow

I think, like many things, the reason a lot of people follow a certain number of servings or ounces or whatever of water per day is that it's measurable. It's much easier to have a specific guideline or set amount that to just say you need to stay hydrated. It might take someone only 2-3 glasses of water a day to stay properly hydrated while it may take someone else 8-10 depending on level of activity, food consumption, chemical consumption, and just uniquenesses of each individual human body. I aim for at least 9 servings of water day (water--not soda or juice or whatever, just water). I do this because it make ME feel better as compared to when I wasn't drinking plain water even though I was having 9+ servings of fluids a day. Everyone is different, but since so many people look for a measurable amount, I think the 8+ servings standard (however made-up it may be ) gives people a set amount to aim for. I'm not saying it's the exact right amount for everyone, but it's not something that's as easy to figure out as, say, calories, which you can get an estimation for by doing equations with your weight and activity level and whatnot. If you tell someone to just drink "enough," they will always ask how much that is, and so we pick a specific amount. Does that make sense?

Jules--I know you realize that water isn't a magic bullet and that cutting out the sugar/calories from the sodas has done your body a WORLD of good, so I know you know that drinking more water HAS helped you (whether the amount be 4 glasses a day or 40 ). I think the rapid weight loss won't last much longer, but you could still be losing steadily depending on your current caloric intake. If you had been maintaining your weight and have since cut, say, 500 calories a day from your intake by cutting out soda, then you should be losing about a pound a week Of course, if you've made any other changes (healthier foods, lower calories, more exercise, etc.), that will continue to boost your weight loss as well.

Thanks Jilly for being so supportive.
I get what you are saying about your "specific" amount theory. There are some of us that need to have those set guidelines to help get us back under control.
I am beginning to believe there are two schools of thought on water.
The first are like us and drink it. I know that I feel 100% better. It can't hurt that the water does help keep me feeling fuller and I truly believe that I was thirsty and not hungy. Reaching for a drink or two of water instead of going to one of the many candy jars in the office has to be much better for my hips. I also believe I was truly dehydrated. I can't drink more than 8-10 8 oz servings of water a day so I don't think I am going overboard.
The second group doesn't like water and if whatever they are drinking works for them great--just don't discount what works for those like us.

I have read many postings and there is not one program that is working for everyone because what works for one person doesn't always work for the next.