You can give her a sippy cup with water in it. I don't think there's any way she would choose water over your milk!
She should have *some* water especially if she's having "dry" solids like cereal or biscuits... it will keep her from getting constipated.
My DD loves water, whether it's in a sippy cup, an open cup, in the bathtub, sucking on a washcloth
and she still nurses just fine!