No one's creating hysteria. No one is suggesting anyone's going to die.
Hysteria yes, death no.
The O.P. observed that using off-peak gas (from his hot water system) as a source of water for his HLT, cut down on brew costs. A great idea... but it's hardly the time for mentioning extremophilic bacteria and heavy metal contamination, surely? Maybe they belong in a microbiological enthusiasts thread?
Sometimes it's the way people type their ideas out, but other times, it's just people being difficult. I hope it's the former in this case.
Some points made in these forums (no matter how valid) are quite often irrelevant to brewers. People posting detailed, yet irrelevant, examples of their knowledge (in their area of expertise) doesn't impress me... Is this breakdown of sacrificial anodes in the slightest way relevant to a decent brew? I see no evidence, because I've brewed many a magnificent beer on my system that uses water from a (god-knows-how-old) hot water system.
Do sacrificial anodes break down in the water over time? Sure they do. Does the plastic from an Esky wall contribute flavours to a final tasting? Possibly. Am I brewing too close to a street carrying heavy traffic and adding unnecessary lead to my brew?? There are
FAR TOO MANY variables outside of this topic that contribute taste effects to worry about this particular example, IMO.
Let's not be silly here - how about we try to keep things in perspective, if your hot water system spits out rusty (brown) water or it tastes like shit, then don't brew with it. But if it smells/tastes fine, then use it and don't be too persuaded by the naysayers! I did.