dipsydoodlenoodle
Fish Gatherer
It depends what water tank you have; my old house had a plastic one; my new house doesn't have a water tank - I've argued and argued with my boyfriend about this and I don't have a water tank.
It sounds like you may have a tankless hot water system. These were common in certain areas of the US (not sure about anywhere else in the world) several years ago, but seem to be spreading across the states. Their initial purchase and installation costs are typically more than a tanked hot water system, or maybe just replacing a tank, but their month-to-month energy consumption levels are lower as the hot water is heated as it's needed rather than having a tank storing XX gallons of hot water at any given time, eventually (and rather quickly) the month-to-month $$ savings pay for the system, usually within a couple to a few years.
Well I'm on the UK so it's definately around the world .