The World Federation One Stop Fiqh

Ruling 268

If someone does not want to perform prayers in a mosque and does not know whether the place designated for wuḍūʾ in the mosque or its pool is a charitable endowment to the general public or only to those who perform prayers in the mosque, he cannot perform wuḍūʾ there. However, there is no problem if people who do not usually pray in that mosque perform wuḍūʾ  in that place or with water from the pool and no one prohibits them from doing so.