Perhaps one or two will be appropriate as starting points for you. Water is required by the body as part of every metabolic process. Humans cannot survive much more than a week without it. Every body cell, tissue and organ must have water to sustain life. Water is required to maintain body temperature, transport nutrients, oxygen and waste, and is a component of all bodily fluids.
Caffeinated beverages have a diuretic effect on the body, causing fluid loss.
If you drink caffeine on a daily basis, you may be losing significant amounts of bodily water. In other words, if you start the day with 1 cup of coffee and 2 cups of water, you are back to a zero water intake. Because of caffeine's diuretic effect, many of us end up with a negative water intake at the end of the day. If your water intake is currently below the recommended 10-12 cups per day, start by cutting back on caffeine consumption. Substitute water for other beverages with meals and strive to take water breaks versus coffee breaks.