We capture and use rainwater for all of our household needs, including drinking and cooking. We are in the middle of a horrible drought (4.4 in rain in the past 6 months--a record) so I'm the water police:). I have never prewashed fabric, at this point anyway. I love the suggestion of "hand washing" in the washer. Great water conservation tip. Sorry, but I have to side with your mom.
I'm going to have to Google Shuriken Packer quilt, it sounds beautiful.