If something falls into a well and changes the smell of the water, all the water must be drawn out. If the amount is large and difficult to draw, it is obligatory to hire four men to draw from it in turns from morning until evening. As for water from sulfur springs, The Prophet صلى الله عليه وعلى آله وسلم forbade using it for medicinal purposes but did not prohibit ablution with it. These are the hot waters found in the mountains that have a sulfur smell.