Ruling on determining the presence of water underground using a stake or other means

Question:
In the orchards of some farmers, in the orchards of Banu Tamim, the land was afflicted with a scarcity of water. One of the farmers dug three wells in his farm, but he was not successful in finding water. A man told him that he could determine the location of the water by driving an iron stake into the ground; if the stake becomes stuck, this man infers the presence of water in that land. He says, "Dig here and you will find water, if Allah wills." The owner of the farm did so and found abundant, sweet water. This puzzled some of the farmers, and they wanted to ask this person to identify a location in their farm so they could reach the water, given their scarcity of it. However, they hesitated, fearing that this man might be using jinn. We ask for an answer to this question, noting that this man is elderly and appears to be righteous. May Allah reward you for your assistance?

Answer:

First: Today is the fourth day of... We ask Allah to relieve the servants, to send down blessing upon the Muslims, and to grant them blessed rain in their hearts and their lands... faith, guidance, and blessed rain.

Second: There are signs and indicators of the presence of water that are known by specialized people, not in the sense of fortune-telling, nor in the sense of using jinn. The scholars mentioned this, including Ibn al-Qayyim (may Allah have mercy on him), who mentioned many indicators by which the presence of water in lands is known, through winds, through mountains, through plants, and other means by which they know the presence of water in the desert and in villages. These are people who know and have tested it, but they are not protected from error; they may err, they may be mistaken, but for the most part they are correct, and they may err in what they assert.
If one finds someone who infers the presence of water by signs, saying that he knows them, whether by a stake, or by something other than a stake, or by anything else, and this has been tested, and it is not known that he calls upon the jinn, or seeks aid from the jinn, or does abominable things; then there is no harm in benefiting from him and making use of him. These people have existed for a long time, in this kingdom and elsewhere, and in Hail as well, there are people known for this.

The intended meaning: There are people who know these things, and if they test it and succeed for the most part, there is no harm in benefiting from them, except if it is known that one of them, or a group of them, engages in abominable matters; in that case, they are prohibited.

Question:..

Answer: In any case, he may infer by whatever he wishes, as long as it is permissible by the Shari'ah, with a shovel he digs with, or a stake he drives, or by climbing mountains to observe the winds and the plants, or otherwise.