R.D.
L., Unless your doctor says otherwise, I don't think water will hurt her. I alwasy just leave a sippy cup with water out on the table for my children to get. IF she is indeed only wanting it because she is afraid she can not have it, she will soon stop when she sees she can get the water herself whenever she wants it. When I potty trained I brought my children to the bathroom every 1.5 hours. If they went potty like a big girl, they got to pick a "potty toy" (a nickle toy that they got to grab from a box I had". After the first week of this, they got stickers for each potty instead of a toy. The stickers eventually earned a bigger toy or activity. This lasted, from beginning to end maybe a month tops.
Good luck,
R.