Purity: Wudu with Usurped Water or Place
Practical Laws of Islam as per the teachings of Ayatullah Sistani
Ruling 266:
Performing wuḍūʾ with usurped (ghaṣbī) water, or with water about which it is not known if its owner consents to its use or not, is unlawful and invalid. Furthermore, if wuḍūʾ water drips from one’s face or arms onto a usurped place, or if the place in which one performs wuḍūʾ is usurped, in the event that he cannot perform wuḍūʾ in any other place, his responsibility (taklīf) is to perform tayammum; and if he can perform wuḍūʾ in another place, it is necessary for him to perform wuḍūʾ in that other place. However, in the event that he performs wuḍūʾ in the usurped place, thus committing a sin, his wuḍūʾ is still valid.[46]
-Ayatullah Sistani, Practical Laws of Islam, Purification (Taharah)