How much water to drink

Just learned from my mentor that a normal person needs to drink at least 1.5 liters of water per day. However those people doing spiritual work and healing need to drink at least 3 liters everyday. For the first time managed to drink two glasses of water on an empty stomach before breakfast. That's an achievement for a person who could not even manage to do one glass of water on an empty stomach before breakfast. Moreover the water was at a normal tap water temperature. I am someone who could not manage even one cup of room temperature water on an empty stomach before breakfast. Today did not even have caffeine or almond milk for breakfast and my brain activity and energy level is at a good optimal enough state