I'd never considered it, but now that you mention it, it makes sense. We've had those water tests done at our house where guys were trying to sell us a water softener. They always mentioned how shampoos and soaps would last longer since you didn't have to use as much. Also, you always notice with soft water that it feels almost like you still have soap on your hands after you rinse. They told us that was because you didn't have all of the soapy residue left over. So I would imagine that it would give you a better shave.