Purity: Ghusl in Public Bath with Unpaid Khums

Practical Laws of Islam as per the teachings of Ayatullah Sistani

Ruling 382:

If someone pays the owner of a public bath from money on which the one-fifth tax (khums) has not been paid, then although he has committed an unlawful act, the apparent ruling is that his ghusl is valid but he remains indebted to those entitled (mustaḥiqqūn) to receive khums.

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