The Natural Philosopher writes:

I really cannot believe this. Just exactly how is all the water you
drink stored anyway, and transported to you?

Hot water sits for long periods in a very old tank under pressure. If
I don't use it regularly it comes out a bit rusty looking. My guess
is that what looks like rust probably _is_ rust, and is thus a hefty
dose of iron. For that reason, I probably wouldn't drink it. And I
don't know what else is dissolved in it.

In the case of cold water, if I haven't taken any in a while I let it
run for a minute. The building is old and I don't know what the
plumbing is made of. Taking a drink immediately from the tap
sometimes reveals a metallic taste.

Honestly, is your roof tank any different at all?

My hot water tank is in the bathroom. The water is electrically
heated.

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