What causes re occuring water blisters on the soul of my feet?

Blisters: Blisters can occur in a wide variety of clinical settings, including autoimmune disorders, drug reactions, infections, genetic disorders, and physical injury. Yours are most likely due to traumatic injury (eg, friction blisters, due to shear forces...Going barefoot in shoegear) or if they are itchy could be secondary to eczema. Try wearing dry socks with dry shoegear to see if this helps.