Unrecognised chronic dehydration is a major health problem. Some people count coffee, tea, colas and fruit juice as water. They are not, and in most cases they will dehydrate you even further. Your cells need water, pure water. Warm or hot water is best, but that's a personal choice.
Any water is better than no water.
Ibsacol has reportedly caused a headache in some people that always has been remedied by drinking more water. It is simple, but you need a new habit to become properly hydrated.