My hair is receding a bit but then could it be something in the water I drink?

I mean it's not that it's really really receding it's just that the line maybe it's because I grab and comb my hair with my hands occasionally then also it could be the Head and Shoulders I'm using should I switch to garnier fruitis also I heard that my friend said that there's chlorine or some chemical in the water and he said he used to have a receding hairline then he stop drinking and for awhile now he said he hair to fuller and thicker Also I'm 17 yrs old