Q. Since it is a Mitzva to eat on Erev Yom Kippur, does that include drinks also and water?
A. Horav Shlomo Millers's Shlit'a opinion is that drinking other drinks is a mitzva. however, water depends if he recites a brocho on it as he wants to quench his thirst.
However, if he is just drinking, as some do before the beginning of the fast, to avoid later thirst, he should also not recite a brocho on it.
Rabbi A. Bartfeld as revised by Horav Dovid Pam, Horav Aharon Miller and Horav Chanoch Ehrentreu Shlit'a.