Is it true that the Prophet, peace and blessings be upon him, or his Companions, used to place a tank of water, over which incantations had been recited, in the mosque for drinking and for carrying to homes? And is it permissible for a man, whom many people frequent seeking ruqyah, to place a large tank in a mosque for him to recite over it to meet the needs of the people?

Ruqyah is permissible by text, action, and endorsement. Whoever can benefit Muslims with it, let him do so, provided that he does not miss out on greater benefits and does not take it as a profession to amass wealth. However, reading Ruqyah over a large tank in the mosque for people to seek healing from has not been authentically reported from the Prophet, peace and blessings be upon him, and it is most likely ineffective. What has been reported from the Salaf is that they used to recite over individuals.