Water.
I drink atleast 3 litres a day (two 1.5 Litre bottles)
One during the day while I work and the other while I'm home at night.
Close to 5 litres on Saturday when I play cricket...
Might be worth checking your BSL as you could have diabetes or diabetes insipidus?
I was drinking quite a large volume of water about six months ago and was actually really worried I might have diabetes (never had a fear of needles until I started dating my GF who has type 1 diabetes). My BSL was fine and for whatever reason I stopped drinking such excessive amounts of water. Now I only drink over 2.5 litres a day if I'm exercising at a high intensity.






and I was fine with that... and I haven't drank alcohol since then which is now over two weeks again, so that has been good to achieve...