Do magnets remove lime scale from water pipes?

Dr Hugh Hunt, Cambridge University

Question: Iíve been told a magnetic field can dissolve lime scale in water pipes. Is this true and how does it work since the pipes and I believe the lime scale arenít ferrous and not affected by a magnet. Tony, Dereham, Norfolk

We put this to Dr Hugh Hunt, from Cambridge University's Engineering department:

I am Hugh Hunt from Cambridge University Engineering Department. Well, there are lots of manufacturerís websites that claim that if you put magnets on your water pipes then that prevents limescale build up on the element of your emission heater. Electronmicrograph of limescaleWell itís obviously in manufacturerís interest to make these claims but lets suppose that in the last year a manufacturer has sold a thousand of these devices and they get one letter which says how fantastic it is, another ten letters that say that doesnít work. Well they can give ten refunds. They have still made quite a lot of money and they can publish that one nice letter and I guess that not be what we are seeing on the websites but now thatís being a bit mean but I am a bit puzzled that there arenít any quoted referred scientific publications out of the mainstream literature.

Surely if there was something really scientific going on here it would be well and truly understood. So I just wonder. Now there are few possible candidate theories all to do with magneto hydrodynamics and water memory and things to do with nucleation and so on, you can read all about these. Where does that leave us? Well I think if you have found that one of these devices works for you, well it doesnít do any harm so you may as well carry on using it. But if you find that it doesnít work then perhaps thereís no surprise in that.