How much water you should drink every day varies from day to day and person to person. It depends on factors such as how much you sweat and how active you are. The more active and sweaty you are, the more you need to drink. I'm a very sweaty person so I drink heaps! :)
There isn't a perfect recommendation for how much water we should drink. Some say that for women it could be around 9 cups/2.2 liters and for men about 13 cups/3 liters. The best advice is to try and see what works for you. Listen to your body, it will tell you what you need: if you're not thirsty and are drinking about the recommended levels, you're probably fine. However, if you feel thirsty or hungry often, and maybe have headaches and/or constipation, it could mean you need to drink more water.
Water is vital for many body functions. Check out this article for 5 inspiring facts.
Facts from Medical News Today 30/11/17