On Thu, 5 Jan 2017 19:09:46 +1100, F Murtz
wrote:

My house is on a slab and I get five volt tingle from the taps when I am
in the shower.
I suspect that when it was built they did not bond the steel mesh to
earth, which they are supposed to do now.

Check, or have an electrician your grounding electrode system. Also be
sure metal piping is bonded around any plastic sections, water
softener and the water heater.