He was then told: “Abū Yūsuf used to say: ‘This well should be blocked. If the water of the former well returns, it should not be reopened; but if the water does not return, it should be reopened.’” He did not approve of this view. The same was reported in the narration of Muḥammad ibn Yaḥyā al-Mutaṭabbib: concerning a man who dug beside another man’s water channel, he said: “He may not prevent him if he digs beyond its protected area, whether this harms him or not.”

The second narration holds that the well may not be allowed to remain and must be filled in. In the narration of Ibn Manṣūr, he said: “No one may dig a well beside another’s well, or a cesspit beside another’s wall, even if it is within his own property.” He was asked: “Can he prevent him from doing so?” He replied: “Yes.” If he has the right to prevent it, then it follows that he has the right to fill it in.

This was stated explicitly in the narration of al-Maymūnī. He said, reporting from al-Shaʿbī, that the latter related the case of a judge who adjudicated between two men, each of whom had a garden next to the other’s. One of them dug a well in his garden, causing the water of his neighbor’s well to flow away. The judge ruled that this man’s well should be blocked: if the neighbor’s water returned, then that settled the matter; but if it did not return, he was required to remove whatever he had put into his neighbor’s well. Al-Shaʿbī said: “The judgment was correct.” Aḥmad admired this judgment, and it was also the position preferred by Abū Bakr, as Abū Isḥāq mentioned in his annotations. He said: “If the cesspit was made before the well, then the owner of the well was at fault for constructing it. But if the well was made before the cesspit, and the cesspit contaminated the well water, the owner of the cesspit must remove it.”

He said: “The well can be tested by placing drops of naphtha in the cesspit and then examining the well water. If the smell of naphtha emerges in the water, it will be known that the contamination of the well was caused by the cesspit.”

As for springs, they are divided into three categories. The first is a spring whose water Allah Most High caused to gush forth, without human beings bringing it to the surface. Its ruling is the same as that of the rivers Allah Most High has made to flow. Whoever has reclaimed uncultivated land with its water may take from it an amount sufficient for his needs. If they dispute over it because of its limited supply, consideration is given to the amount of uncultivated land reclaimed with its water. If some of them preceded others in reclaiming land, the one who was first to do so has the right to obtain from it enough water to irrigate his land, followed by the one next in precedence. If the water available for irrigation is insufficient for some of them, the shortfall would be