An extract from "The Skeptical Equirer" on this subject:-
" There is apparently no consensus among magnet vendors regarding the mechanisms by which magnetic water treatment occurs. A variety of explanations are offered, most of which involve plenty of jargon but little substance. Few vendors, if any, offer reasonable technical explanations of how magnetic water treatment is supposed to work.
The important question here, though, is whether magnetic water treatment works. In an effort to find the answer, I conducted a search for relevant scientific and engineering journal articles. I describe the results of this search below.
More than one hundred relevant articles and reports are available in the open literature, so clearly magnetic water treatment has received some attention from the scientific community (e.g., see reference list in Duffy 1977). The reported effects of magnetic water treatment, however, are varied and often contradictory. In many cases, researchers report finding no significant magnetic treatment effect. In other cases, however, reasonable evidence for an effect is provided.
Liburkin et al. (1986) found that magnetic treatment affected the structure of gypsum (calcium sulfate). Gypsum particles formed in magnetically treated water were found to be larger and "more regularly oriented" than those formed in ordinary water. Similarly, Kronenberg (1985) reported that magnetic treatment changed the mode of calcium carbonate precipitation such that circular disc-shaped particles are formed rather than the dendritic (branching or tree-like) particles observed in nontreated water. Others (e.g., Chechel and Annenkova 1972; Martynova et al. 1967) also have found that magnetic treatment affects the structure of subsequently precipitated solids. Because scale formation involves precipitation and crystallization, these studies imply that magnetic water treatment is likely to have an effect on the formation of scale.
Some researchers hypothesize that magnetic treatment affects the nature of hydrogen bonds between water molecules. They report changes in water properties such as light absorbance, surface tension, and pH (e.g., Joshi and Kamat 1966; Bruns et al. 1966; Klassen 1981). However, these effects have not always been found by later investigators (Mirumyants et al. 1972). Further, the characteristic relaxation time of hydrogen bonds between water molecules is estimated to be much too fast and the applied magnetic field strengths much too small for any such lasting effects, so it is unlikely that magnetic water treatment affects water molecules (Lipus et al. 1994).
"http://www.csicop.org/si/9801/powell.html
