Aquagenic pruritus is water based allergy, but I would expect itching as a prominent feature.In your case it is more like a photosensitivity reaction.Try water resistant sunscreens.
It can be aquagenic urticaria. Water urticaria, or aquagenic urticaria, is a rare condition in which hives develop within 1 to 15 minutes after contact with water. The hives last for 10 to 120 minutes and do not seem to be caused by histamine release like the other physical hives.
Water urticaria is diagnosed by applying tap water and distilled water to the skin and observing the reaction.
I would suggest that you get it evaluated from a dermatologist.The other possibilities are of dermatitis,contact dermatitis or eczema.
Hope it helps.Take care and pls do keep me posted on how you are doing or if you have any additional doubts.Kind regards.