How much water should you drink?
Studies show a good baseline is to drink at least half your body weight in ounces of water, every day.
Mild dehydration (fluid loss of just 1-3%) can impair energy levels and mood, and lead to major reductions in memory and brain performance.
Your exercise habits affect the amount of water you should be drinking, as well. The American College of Sports Medicine recommends adding 12 ounces of water to your daily intake for every 30 minutes that you plan to work out.
REFERENCES
How to calculate how much water you should drink
https://www.umsystem.edu/totalrewards/wellness/how-to-calculate-how-much-water-you-should-drink/
Mild dehydration impairs cognitive performance and mood of men. Ganio MS, Armstrong LE, Casa DJ, McDermott BP, Lee EC, Yamamoto LM, Marzano S, Lopez RM, Jimenez L, Le Bellego L, Chevillotte E, Lieberman HR. Br J Nutr. 2011 Nov;106(10):1535-43. doi: 10.1017/S0007114511002005. Epub 2011 Jun 7.
American College of Sports Medicine Roundtable on Hydration and Physical Activity: Consensus Statements. Douglas J. Casa, PhD, ATC, FACSM*, Priscilla M. Clarkson, PhD, FACSM, and William O. Roberts, MD, FACSM. Current Sports Medicine Reports 2005, 4:115–127. Current Science Inc. ISSN 1537-890x