I've lived in some countries in Europe where the water is so hard that it is only used for coffee, tea, and cleaning. If people wanted to drink water, they had to buy it in bottles. What I did during those times was washed my hair with a clarifying shampoo (once in a while I used baking soda).
I understand from different articles and the local water department that most American homes have hard water.
Because I usually shampoo with a clarifying shampoo, I wouldn't know if the water was soft or hard. So, after I shampoo, I'm always able to style it.
When I'm in the pool or the ocean during the summer, I follow the same method. I do coat my hair with sunblock lotion before going into the water, though.
Mod CG-Naturally Highly Porous and Dry SPRING REGIMEN-This list is not exhaustive...
Pre-treat: coconut oil
Clarifier:hiatus for now
Cowash: HE The Sleeker The Butter, HE NOYF w/Mandarin
PT: hiatus for now/DT:Redken Diamond Oil Deep Facets, Living Proof PHD
LI/Detangler: CK Satin Roots, Nu-Gro Leave-in
Oils: tamanu/Moisturizers: various
Stylers: CK Curl Factor, AH Cupuacu & Burdock Sweet Hair Pudding
*experimenting and loving it!