Yes, he’s simply wrong.
Water has little effect on either permanent or temporary magnets. But let’s take a fair look and use this moment to explain how both types are created, and why water plays almost no role at all.
First off, temporary magnets. Take an iron nail. Stroke it with a strong magnet, and the magnetic domains inside, the tiny neighborhoods of aligned atoms, begin to rotate into the same direction. Once enough of these domains point the same way, the nail becomes a temporary magnet.
But this alignment is fragile. A temporary magnet can lose its magnetism through heat, physical shock, or a stronger, opposing magnetic field. Water, on the other hand, does nothing.
Even weak temporary magnets, like a magnetized iron nail, doesn’t lose magnetism just because it gets wet. If the nail rusts over time? That’s chemistry changing the metal’s structure, not water scrambling domains.
Secondly, permanent magnets are a bit of a different story. They are made from special materials, like neodymium or ceramic composites, that naturally resist having their domains scrambled. Manufacturers expose the material to a very strong magnetic field, align nearly all domains, and lock them in place by cooling or pressing the material so its atomic structure “freezes.”
And again, water has almost no effect. You can dunk a neodymium magnet in water all day. The only danger is corrosion or rust if the magnet isn’t coated. But the magnetism itself remains untouched.
If anything, these moments remind us that science is usually far simpler — and far more interesting — than the sound bites we hear. And it gives us a chance to revisit how magnets actually work, rather than letting myths pull us away from the truth.