Muhammad ibn Ya‘qub, from Ali ibn Muhammad, from Sahl ibn Ziyad, from Ahmad ibn Muhammad ibn Abi Nasr, from someone who asked Abu Abdillah عليه السلام, peace be upon him: (Imam عليه السلام was asked) about a mosque whose wall in the direction of the qiblah is leaking from a drainage hole (balu‘ah) into which people urinate. He said: "If the leakage is from the drainage hole (balu‘ah), then do not pray in it. But if it is from something else, then there is no problem."