Hot water dissolves lead more quickly than cold water and is therefore more likely to contain greater amounts of lead. Never use water from the hot water tap for drinking, cooking, or making baby formula.
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.
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.
Yeah the real reason is that the inside of a hot water storage tank is nasty. Because of the way heat flows up, the hot water fills from the bottom and drains from the top. All the sediment and dirt and minerals collect at the bottom.
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”.
The same advice applies
Impossible, as the American band Rammstein once said “We’re all living in Amerika, Amerika ist Vunderbar”
And then the rest of the song is in
GermanFar Western Pacific American
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.
Well, it’s not been legal in the UK since 1970 to sell or install lead plumbing.
And the official Department of Water Inspectors (https://dwi.gov.uk/) reported only 50 cases of lead pipes in last year’s inspection
The use of lead solder and brass fittings has only been illegal in the uk since 1999, and these are still legal to use in central heating systems. This leads to people having access to these fittings and products, and them being used illegally.
“WaterSafe Warning after Kitchen Fitter Fined for Illegal Use of Lead Solder on Water Pipes” https://www.watersafe.org.uk/news/latest_news/watersafe_warning_af/
Unfortunately this problem is sort of universal and I imagine if I google other countries I will find similar.
To be fair, lead solder is far far far less risky than last piping
That is a straw man argument, but I’ll indulge again.
No amount of lead is safe, and a random sampling of newly built houses testing water from the cold kitchen tap as well as hot and cold from the bathrooms found lead above the current regulatory limit, and 5 times higher than the proposed new regulatory limit.
https://leappalliance.org.uk/litw-blog-15/
https://www.ifeh.org/docs/scientificreports/scottish_new_homes_lead_survey_ summary.pdf
One study has shown a clear response in infants where blood lead levels increased by 1µg/dL with drinking water that exceeded 5 µg/L. This is already worrying since it is now believed that blood lead levels as low as 1-2µg/dL result in negative health effects associated with fertility, neurological, cardiovascular, and renal disorders.
https://thewaterprofessor.com/blogs/articles/drinking-water-lead-and-iq
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
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.
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.
Ah, so it was water heater corrosion. That makes more sense.
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 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?
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.
sad soup slurp noises
Don’t do it. fr.
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…
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
Tons of old houses have lead fixtures still, unless they’ve personally paid a plumber to replace all of the pipes in the building.
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.
The post is rather thin, but I was initially upset about this post because I can’t read.
I was like: I’m going to drink hot water whether you like it or not! Took a while for my brain to process “hot tap water”.
AFAIK, where I am at we do have only PVC and there is no lead pipes. Or they are to be found in a very specific places, occasions and whatnot.
There still might be other heavy metals that accumulate. It’s the water supply, not just the pipes.
I definitely made a few cups of noodles from the summer camp hot tap in my bunk. Whoops.
