Hawzah News Agency – Many big companies and business in the West employ large numbers of employees who work in offices about whose ownership they have no idea. So what is the ruling on:
1. Praying in those offices and using the water for wudhu?
2. If praying there is problematic, what would become of past prayers said in those places?
Answer: 1. There is no problem in praying in those places nor in using the water for wudhu as long as it is not known to have been usurped.
2. If it becomes clear after saying the salat that the property was usurped, the past prayers are valid.
2. If it becomes clear after saying the salat that the property was usurped, the past prayers are valid.
Source: https://www.sistani.org/