I wanted to know is there anything known as water allergy?

There is: It is very rare, called aquagenic urticaria, welts and /or itching with exposure to water. It occurs mainly in women. It has to be differentiated from cold-induced urticaria, where the rash due to cooling of the skin after getting wet and not the exposure to water. Also, there are certain diseases where exposure to water causes itching without welts.