Waterproof 1, Water resistant 0 (unless your intent is for _resistant)

I have worked in the softgoods/footwear industry for roughly a combined 8 years prior to Industrial Design school. It seems as if I was never certain between the water resistant vs waterproof debate. So here it is...

To be truly "waterproof", the garment must be made from a "waterproof" fabric and have sealed, or taped seams so that rain does not leak in through the small perforations made by sewing needles during the construction of the garment. Sealing and taping seams takes special equipment and extra time. As such, it adds substantially to the cost of the garment. If the garment is made from a "water resistant" fabric, that usually means that a coating has been applied to the fabric to help repel water. Water resistant fabrics work very well for light rains, or drizzels, but may get soaked over time and are not considered to be "rain gear". If you are looking for protection from rain, you must look for garments made from "waterproof" fabrics, not "water resistant" fabrics.

–Bicycleapparel.com