We have hard water too. I use Epsom Salt in my baths. It does help to feel cleaner. It helps to prevent water deposits and soap scum build up on the skin. In the winter, you'll really notice the havoc it(hard water) does to the skin. Sea Salt is good. I've never heard of using table salt . Vinegar is also good to use in the bath to tame down the hardness.
If anyone has any suggestions for after SHOWER rinsing.... I hate how my skin feels after a shower. It stays slippery from the soap not all coming off. And it flakes horribly after drying. That I am guessing is the soap and the hard water. I hate it though! I poured some vinegar on the worst places the other day and that seemed to help. But I guess I didn't use enough. Is there a recipe, or a secret to rinsing?