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Wouldn’t that only apply if there’s lead plumbing inside your house in between the water heater and the tap?
Yes, but there's other metals than can dissolve in hot water, like copper and cadmium
There shouldn't be any cadmium in your plumbing. Copper while actually a nutrient in very very small doses, would only be a problem in severely corroded pipes where cold water isn't helping you.
Any heavy metals will accumulate in your water heater and the hot water could potentially keep it in suspension. I bet it's worse if you have lead pipes.
Nobody in the last century+ has lead freshwater pipes.
That said, some of our underground infrastructure is very old, and those old iron pipes had fittings sealed with lead and oakum.
Water flowing through such pipes have pH and chemicals carefully controlled to avoid that lead corroding or dissolving. The Flint, Michigan disaster was a direct result of not managing water chemistry correctly, but there are hundreds if not thousands of communities at similar risk who are kept safe by water scientists and engineers doing their job correctly.
That said, hot water tanks do accumulate minute quantities of undesirable metals over time, and depending on a wide variety of variables between the water source and your tap it could result in unhealthy levels of things you don't want to consume.
So yeah, don't cook or drink from the hot water tap.
At least here in Germany lead pipes were only forbidden in new houses after 1973. For old houses they should be replaced by January 2026.
That's not totally true. I've personally removed lead pipes from houses that were built in the 1940s to 1960-1961. They stopped that shit sometime in the '50s or very early '60s here in the US, depending on the state. So it would be true that no house built in the last 65-75 years would have lead pipes, any old houses that have been sitting empty for the last few decades may actually still have some lead pipes.
Well damn. Lead restrictions weren't Federal law until 1986. TIL.
https://www.epa.gov/sdwa/use-lead-free-pipes-fittings-fixtures-solder-and-flux-drinking-water
Although some areas added local restrictions starting in the 1920's, industry lobbies kept the things on the market for decades. Ugh.
Yeah this is fear mongering bullshit.
The reason you care about dissolved solids is because of minerals tasting like shit and making your food taste mineraly.
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No lead pipes. 70C water temp against legionella. Yearly water quality tests in all public buildings. Drinkable tap water by law in any rental property. Europe <3
Even without lead pipes, if you have an electric water heater, the sacrificial anode rod leaches all sorts of shit. Seriously, just use cool water in a kettle. Mine usually takes less time than my pipes do to warm up when washing dishes.
If you have a high pressure hot water system, then the heater doesn't touch what comes out of the tap. In those you have a closed system from the heating to a tank. That tank contains fresh water, but the heating loop only interacts with it via a heat exchanger.
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What if I don't live in America, and my local infrastructure is sanitary?
America's water infra is fine. Flint was a case of mismanaging the water supply. (Neat write up in this thread.) Jackson Mississippi is the only other place I'm aware of modern issues, and I wouldn't take MS of an example of American anything except for "bottom of the barrel everything".
It's actually common knowledge that the vast majority of American water infrastructure is now nearly 100 years out of date, and Flint was just one regional example of potential waiting crises.
Source(s):
John Oliver Brought Out Sesame Street’s Elmo to Explain How We Can Stop Poisoning Our Children
The Lead Pipes in Flint Are a Tiny Part of a Huge Lead Problem
The same advice applies
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A new home in the United States does not have lead pipes inside of it. There could be lead pipes outside, but from the water heater to the tap will definitely not be lead.
Some people mentioned hot water heater buildup. But this is supposed to be a new house so there is none. Also it would depend on the style of water heater. As well as the incoming water quality.
Some people also mentioned electric kettles. Those are not as common as you might believe in the United States. Of course it varies but this is not the UK.
Statesian here. I have one kettle in my bedroom one in my kitchen, and one in my office. Tea waits for no man
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Have you ever smelled or descaled the inside of an old hot water tank? Its delightfully putrid and I would never want to drink the stuff coming out of there whether its technically safe or not
That's only true in America, where your Health and Safety Standards are shit.
Might be true in parts of Africa and China too, along with other places with a bad standard of human rights.
Growing up in the US I learned this exact thing was why there were two taps in the UK instead of a shared tap. That and Legionnaires growing in the hot tanks.
Yeah that's not been true for about 50 years.
We replaced all our lead, and it's a legal requirement to if you find a lead pipe in a system, replace it no matter what (even in listed buildings) or disable the outputs entirely (the latter is more common in VERY OLD buildings, with people then adding a new system somewhere else, sometimes with exposed pipework rather than having to potentially damage walls.)
We also just don't do hot water tanks any more usually, instead doing on-demand boilers.
Does mean that the hot runs cold for about a minute, but it balances out
The hot runs cold for a minute with a tank too. It takes awhile for it to reach the tap.
It's still legal for plumbing parts that contain lead to be used here in Australia.
It was supposed to be banned last year but they extended the dead line twice because the plumbers were crying.
It's now meant to be fully phased out in May 2026.
There may be more lead in your country than you think, even if lead pipes are banned.
Multiple schools here have had lead found in their water. It's crazy.
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This seems....questionable. The entire information given is two sentences. This seems like something an eighth grader wrote for a school project.
'Hot water dissolves lead faster'. Ok, how much faster? I feel like the trip from the water heater to my sink is negligible even if I had lead pipes, which I don't.
If anyone has anything more substantial, please post it.
Chemical engineer here. The difference in temperature between your cold and hot water supplies is what the problem is, and I would imagine this is not a problem at all in modern plumbing systems. Your cold water supply is usually about 50-60 deg F (10-15 C) while your hot water supply us usually set to 140 F (60 C). Solubility of some lead salts in water are given in this table with lead chloride being about 0.8 g/100mL at 10 C and 1.98 g/100mL at 60 C, so about 2.5x more soluble. The rate itself is a more complicated relationship, but it increases rapidly as well. Temperature has a big effect on these things.
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When I moved into my house, I ran tests on my tap water, and found that my hot water had higher levels of iron and other metals dissolved in it. This is likely corrosion from the water heater tank. After I replaced the anode rod, the tests came out nearly identical.
All of the levels I found were within the legal limits for human consumption, so it would've been fine... But maybe there are cases where that isn't true. The tests were very cheap, and Home Depot near me offers a 3 test kit (including lead) for free, near the water filter section. It's worth testing to be certain.
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Wouldn't all the dishes and utensils be exposed to lead when you use the dishwasher then? Or is it negligible as long as it's not directly ingested?
I think it's negligible compared to ingesting. I think most dishwashers do a final cold rinse, yeah? I could be wrong on that though.
I've never seen a dishwasher with 2 supply lines, they usually only hooked to hot.
Or cold with an internal heater, but still a single supply line.
We need that dishwasher guy to look into all of this.
He did already and that's why we know most dishwashers (in the US) are fed by one line coming from the hot water tap.
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The steam that comes out of dishwashers I've used after washing would seem to indicate otherwise. Wouldn't that temperature shock be dangerous to the ceramics?
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I'm sorry is this some kind of American joke i'm too European to understand?
It's fr and not a joke. If you grow up here, you're usually told. Some aren't aware of it though. We keep giant hot water tanks ready to go.
This is the typical think most people have for old construction. Not sure about new construction. It's usually stuck in a closet or the basement:
I have a hot water recirc system that pumps hot water to the cold tap. Does that explain why I've started turning on my car's hazard lights when it rains?
The other issue is a hotwater tank can breed bacteria if not hot enough, and if people are not thoroughly boiling and cooling for baby formula and just using hot tap water you could expose the babes to bacteria
I have a gas heater, so the water never sits around in some tank so I'm fine. We also do not have lead pipes...
FYI a gas heater can have a tank. I think you are referring to a "tankless" heater. They are nice, but expensive. I had one in my previous house.
Really not even that expensive. I just installed one and it was like $1400, but it gets a fuel efficiency rebate of $600.
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In the early 70s the city I used to live in replaced all their old wooden water lines with concrete/asbestos pipes. They are now digging up the asbestos lines and replacing them with plastic. I do not know what the eventual plumbing will look like once they find out how the plastic is killing them.
Probably start installing wood plumbing.
For countries without lead issues, it is still a bad idea as hot water tanks can be hosts to a bunch of shit you definitely don't want to ingest.
Pretty sure most pipes don’t have have lead these days but lead the soldering in the joints of the pipes it is still pretty common
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I definitely made a few cups of noodles from the summer camp hot tap in my bunk. Whoops.
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this post was submitted on 10 Nov 2025
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