Permissibility of dowsing in Islam
5-6-2005 | IslamWeb
Question:
There used to be persons who with the help of pendulums or "Y" shaped or "L" shaped metal rods walk through an open field or ground and find out spots where there is abundance of water. They call it dowsing or water diving. Is it Islamic? Can a Muslim employ these persons including Muslims who have full faith in Quranic verses which proclaim that Allaah only knows what is hidden and that Allaah reveals whatever He wishes to those whom He wishes (Aayat Al-Kursiyy - 2:256).
Answer:
All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad 
is His slave and Messenger.
If the use of what is mentioned in the question to discover the places where there is water is based on scientific facts, like for instance if such devices have a magnetic impact when approaching water and the like, then it becomes permissible to use this method or seek the help of those who do it to extract water. This is not considered as magic or fortune telling which is Islamicly dispraised and forbidden. Besides, this does not contradict the fact that Allaah Alone knows the Unseen. Indeed Allaah gave the ability to some of His Creatures to discover water under the ground, like the hoopoe. Al-Haakim 
reported that Ibn 'Abbaas 
said: “The hoopoe used to indicate to Prophet Sulaymaan (Solomon) 
where there is water under the ground.”
Moreover, Ibn Al-Qayyim said: “The hoopoe is one of the knowledgeable animals [in finding water]; it has an insight about places where there is water under the ground, the matter which no one else could predict [sense].”
However, the fact that the hoopoe knows the places where there is water under the ground, and the use of scientific methods in finding such places does not contradict the fact that Allaah Alone knows the unseen; rather, this is something that Allaah taught His Creatures so that they would achieve their benefits and fulfil their needs.
Allaah Knows best.