Actually drinking water is a habit worth having, not breaking...

How long does it take you to do 20 miles?

I try to drink at least one bottle per hour, and wouldn't mind drinking a little more. It takes me about an hour and a half to do 20 miles, so you would be right on pace for me.

Modern American's generally don't drink enough water... and some see this as a major factor in the growth in numbers of dialysis centers, so I would suggest that you don't try too hard to limit your water consumption.

There are some ways to squeeze a couple more water bottles on your bike, and you can usually find some way to refill along the way... Try these alternatives rather than limiting intake.

You can drink too much water, but that takes some pretty intensive drinking, so if you are out for a long ride, adding some electrolytres might be a good idea in some of your fluids.