Purity: Ruling on Doubt About Purification of Urinary Outlet or Back Passage

Practical Laws of Islam as per the teaching of Ayatullah Sistani

Ruling 67

If a person doubts whether or not he has purified the anus or urinary outlet, it is necessary that he purify it even if he habitually purifies it immediately after emptying his bowels and/or bladder.

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