Answered by Mufti Yusuf Mullan
After my menstruation had finished I performed ghusl but did not wash my hair (i.e. with shampoo) but did wipe over it with some water. Is my ghusl valid? After that, I also prayed my salat, will they be valid also? I can’t really remember where, but I read somewhere that its OK if you miss something out of ghusl either accidentally or because you did not know it was part of it. I’m not sure whether that is correct.
Wa alaikum salaam,
A condition for the validity of the purificatory bath is that water must reach every portion of the body including all of the hair. Only when hair is braided (for women) it is permissible to not undo the braids and simply ensure water reaches the roots of the hair. [Ibn Abidin, Radd al-Muhtar]
In any case, simply wiping over the hair with some water is not sufficient. As such, the bath was not valid and all subsequent prayers will need to be repeated.
And Allah knows best.