R. Thomas of Ravensbourne asks :-

How do scientists explain water divining?

Bernard Howard, a member of the New Zealand Skeptics and who had examined such claims, responded.

Controlled tests of claims of water divining have been carried out in several countries. In one experiment, in Germany, pipes were buried and connected so that water could be made to flow or not, unknown to the diviners and those around them. In another, objects of various materials, of the individual diviner's choice, were hidden in plastic boxes aligned on a table. In each case the tests were started only when the diviners expressed themselves satisfied with the arrangements.

In both tests, none of the diviners scored better than chance, They failed to detect water or any other material any better than if they were just guessing. All of the tests which I know of have failed to show that water diviners have special powers. The twitching of the divining rod can be explained in purely physiological terms. It results from involuntary movement of the muscles under prolonged tension. I understand that a professor at the Otago Medical School confirmed this some 60 years ago.

I am told there are few, if any, water diviners in areas where underground water is ubiquitous (eg Christchurch) or almost non-existent (eg Central Otago). They are more in evidence where underground water can be found at random often enough to maintain the diviner's credibility. South Canterbury and Southland are such places.