Solid shampoo bars function better when used with soft water. If you have hard water, it's the minerals that cause the scales on the hair to stand up. The soap molecules will "grab" the minerals in the hard water and leave those deposits in your hair. This will give you a "waxy" feeling, and your hair will look like straw when it's dry. Not pleasant. Soft water and acid rinses close down those scales so the minerals and soap can be washed out.
So how do you know if you have hard water or soft water (aside from trying a shampoo bar to find out)? If you live in a city that gets its water supply from a river, then you will likely have soft water. If you live in a city (or rural area) that gets its water from wells, then you will likely have hard water. Many people who live in an area where the supply of water comes from wells own a water softener to soften their water. Some well water is more mineral-rich—and some less so.
If you have not had good luck with shampoo bars, it is very likely that you are dealing with mineral-heavy water issues. For a customer review on a shower head filter that can remove most of the minerals in hard water, see our page HERE. Our family has been using our shampoo bars since 2009 with happy results—and zero waxies. But our water is soft. The good news is—if you have hard water, you can still use our shampoo/body bars on your body!
For more information on how to use a shampoo bar, see our article HERE.