Purity: Obligation to Wipe the Head

Practical Laws of Islam as per the teachings of Ayatullah Sistani

Ruling 248

After washing both arms, one must wipe the front part of his head with the wetness of the water that has remained on his hand. And the recommended precaution is that one should wipe with the palm of his right hand and wipe from top to bottom [i.e. in a direction towards his forehead].

-Ayatullah Sistani, Practical Laws of Islam, Purification (Taharah)