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Comment by bxparks | Hacker News Reader

That's interesting. But don't drink the hot water from the hot water tank. It can be dissolved with unhealthy minerals and chemicals. A few years ago, I had to replace a couple of hot water tanks. When I drained them, the last few gallons at the bottom of the tanks looked like yellow vomit, it was seriously disgusting.

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It’s the same minerals that you ingest when you drink cold water, just more concentrated.

It’s mostly just magnesium and calcium salts, likely carbonate but some sulfate as well, depending on the chemistry of the water.

A bigger concern with drinking hot water is bacteria if you don’t keep the tank hot enough, or lead from soldered joints. Hot water will leach stuff from your plumbing faster than cold water.

But overall, in a normal, modern system, drinking hot water from the tap isn’t particularly risky.

That's why you're supposed to purge your hot water tank periodically.

Also keep in mind that yellow sludge comes from somewhere... like the cold water coming into the hot water tank. So... it's probably in the "healthier" cold water no different.

Concentration of bad stuff matters though.

As the deposits indicate, the concentration of "stuff" decreases as the water flows through the tank.

Right, but if it’s sitting as a solid in the bottom of your hot water tank, it’s not in the actual water coming out (or at least less of it).

The solubility of some minerals, such as lead, increases drastically with higher temperature (https://www.bbc.co.uk/bitesize/guides/z4s48mn/revision/2). Hot water will have much higher concentrations of those minerals compared to cold water. This is not a closed-system, steady state flow equation, since the hot water can pull in additional chemicals from its environment: metal or plastic pipes, fittings, anode rods (aluminum and zinc). The lining inside the hot water tank is made from many different materials, including synthetic polymers (https://www.bijlibachao.com/water-heaters/coating-storage-wa...), which can degrade over time and leach more chemicals into the hot water. Finally, bacteria (e.g. Legionnaires) can grow in the water tank if the water is not hot enough.

This article from the Denver water department says, don't drink the hot water: https://denverwatertap.org/2017/12/13/psa-dont-drink-cook-ho...

Yup. I mentioned the same in another reply.

Which makes me think ... always ask for "no ice" when you are at a bar or restaurant. Unless you know how they make it.

I think that's a pretty un-based fear. Almost certainly any restaurant, and especially a bar, will use a professional ice making machine. At the volumes if ice they go through, it wouldn't make sense to make it in any other way.

This thinking would lead to ‘no everything’

It would actually be kind of funny to go into a restaurant and refuse to order anything because you don’t know how anything is made.

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