I liked Elkor Alish's quote " Dont play with 240 volts kids, it will hurt your pocket or hand " etc.
I cracked up, cause its so bloody true. Electricity, the silent killer.
I put an alarm system into a electricians house. He had been a sparky for 40 years. He said "electricity is like your x-wife and your wallet, once it gets hold of ya, it will never let ya go til the day you die". So very true.
I am betting its not the hot water system. I am looking forward to hearing what the culprit is.