These things are quite common in some parts of the world. If you're not familiar, the reason they give shocks and tingles is that they have unsheathed heating elements i.e. the live resistance spiral is in contact with the water. This enables them to be made smaller and cheaper, a 5kw element (which is all you need in a warm country where the feed water is never cold) is just a few inches of Nichrome coil. Between the element and the rose the water flows over an earthed electrode which is supposed to collect the earth leakage from the element and bring the water back to earth potential, provided someone has bothered to connect the earth lead (usually by taping it to the water pipe, as has been done here). This configuration, allied with the lack of RCD, makes the tape joints in single-insulated cables in zone 1 seem a minor detail.