Water is essential to good health, yet needs vary by individual. These guidelines can help ensure you drink enough fluids. … Although the “8 by 8” rule isn’t supported by hard evidence, it remains popular because it’s easy to remember. Just keep in mind that the rule should be reframed as: “Drink eight 8-ounce glasses of fluid a day,” because all fluids count toward the daily total.

http://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/water/art-20044256

Click the link above to find some guidelines on how much water and other fluids, like coffee, you should drink in a day.  Having an in-house water cooler and coffee services makes it much easier for employees to stay healthy & productive with convenient access to lots of fluids.