I would suggest buying bottled water for her. Soft water is not recommended for human consumption on a regular basis http://www.triangularwave.com/f7.htm
so--if it's not suggested for human consumpution, I would definitely not suggest it for a pet. Distilled water is also to be avoided due to the process that is involved in 'distilling'. On a short term basis, it would probably be fine, but for long term consumption, consder purchasing gallon jugs of springwater given your situation. Please let me know if I can assist further.