I am going to suggest something completely different to the common folk law.
Drinking is not particularly important or relevant to the issue!
Drinking is very important to help the sale of botted water “drink our product and you will be healthy”.
Even if it is an overpriced and environmentally unfriendly product.
How much pollution is caused by packing water in plastic bottles and then transporting it in some cases half way around the world?????????
The important issue is hydration there are several issues that affect hydration such as
Relative humidity
Temperature
Activity levels
A guide to how hydrated you are is your urine output.
If you are urinating regularly say about every 90 min and you urine is pale in colour you should be adequately hydrated.
If you are urinating infrequently or the urine is dark you should try and drink more.
Remember there is a lag between drinking and the water being absorbed so if you expect to be very active there would be an advantage to having a modest drink about 10 minutes before the activity sipping water during the activity would be better than having a large drink afterwards.
Of course if you feel thirsty have a drink.
