Purity: Insufficient Moisture for Head and Feet
Practical Laws of Islam as per the teachings of Ayatullah Sistani
Ruling 257
If the moisture on one’s hand is only sufficient for wiping his head, the obligatory precaution is that he must wipe his head with that moisture, and for the wiping of his feet, he must take moisture from his beard.
-Ayatullah Sistani, Practical Laws of Islam, Purification (Taharah)