In this version you can see how I'm taking time to emphasize "CUPS." This version helps clarify that I want to know specifically the number of cups that are being drank on a daily basis. Plus I put the "HOW-MANY" and the end which fits in nicely with traditional ASL grammar. WATER CUPS YOU DRINK EVERYDAY HOW-MANY YOU?

There are some people that will insist you should do the sign "EVERYDAY" as the first sign in this sentence.
Honestly, I don't think "time/tense" is instrumental to this sentence (conjugation of verbs and such).
For simplicity sake I'm just going to show you this general version: WATER YOU DRINK EVERYDAY HOW MANY CUPS?