Water?

Check which version of MFP Android you are using (Menu > Help > About Us). MFP just released MFP 5.4 for Android; if it is a bug, you can comment here - community.myfitnesspal.com/en/discussion/10301860/android-5-4-release-notes-discussion#latest.

I can't be of much more help, because I disabled automatic Play Store updates, and I am still using MFP 4.8 for Android, and the Add Water feature still works on that version.

I have a Droid as well and find the water setting by tapping the little blue circle with the + in it on the bottom right corner of the screen. Water is the second button from the top when the selections pop up.