Water Spots on Clothing?

I find this to be a curious question. The only fabric I can think of that might show water spots is silk which sometimes needs to be dry cleaned.

Are you sure you are getting all the soap/fabric softener out of the clothing before drying? Try using white vinegar in the rinse water instead of fabric softener. that may help your situation. Or, you can rinse your clothing twice. I think the spots you see on your clothing are from fabric softener or perhaps laundry detergent rather than from minerals in your wash water.

Good luck!