# Drinks from the hot tap **URL:** \ **Category:** Factual Questions\ **Created:** [December 20, 2011, 9:43pm UTC](https://boards.straightdope.com/t/drinks-from-the-hot-tap/606891 "2011-12-20T21:43:35Z")\ **Posts on this page:** 12\ **Page:** 1
**Author:** ![codgerone](https://avatars.discourse-cdn.com/v4/letter/c/c37758/32.png) [@codgerone](https://boards.straightdope.com/u/codgerone)\ **Post date:** [December 20, 2011, 9:43pm UTC](https://boards.straightdope.com/t/drinks-from-the-hot-tap/606891/1 "2011-12-20T21:43:35Z")
Years ago when I was just a kid I remember my old man telling me that you should never use water from the hot tap for making tea or coffee and it stuck with me ever since. Something to do with stuff in the hot water tank that you wouldn’t want to ingest. It’s only taken me 40 odd years to query this but is there any truth in it? Would making instant coffee from the hot tap kill me? ---
**Author:** ![Inner\_Stickler](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/inner_stickler/32/318_2.png) [@Inner\_Stickler](https://boards.straightdope.com/u/Inner_Stickler)\ **Post date:** [December 20, 2011, 9:49pm UTC](https://boards.straightdope.com/t/drinks-from-the-hot-tap/606891/2 "2011-12-20T21:49:19Z")
My parents had the same stricture and my understanding was that it’s a preventative thing. If there’s a chance that lead solder has been used in the water pipes, hot water can leach out the lead and carry it through to the faucet. If you’re showering or doing dishes, no biggie but if you’re cooking, you may then ingest lead. I would totally believe it if it’s all hogwash, however. But that’s the explanation my parents gave me. ---
**Author:** ![KneadToKnow](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kneadtoknow/32/3999_2.png) [@KneadToKnow](https://boards.straightdope.com/u/KneadToKnow)\ **Post date:** [December 20, 2011, 9:51pm UTC](https://boards.straightdope.com/t/drinks-from-the-hot-tap/606891/3 "2011-12-20T21:51:17Z")
This has come up before. I’ll search, but I seem to remember the rationale boiled down to having something to do with hot water leeching toxins out of the plumbing. Whether the rationale was an actual thing to be concerned about, I can’t recall. ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [December 20, 2011, 9:52pm UTC](https://boards.straightdope.com/t/drinks-from-the-hot-tap/606891/4 "2011-12-20T21:52:33Z")
[http://www.charlestonwater.com/water\_faq.htm#hot\_water\_cooking](http://www.charlestonwater.com/water_faq.htm#hot_water_cooking) > [@Charlestonwater.com](#): > > …you should always use the cold water faucet for drinking, cooking, and especially for mixing infant formula. Hot water from the tap comes from your hot water heater, and it may contain impurities. Also, if you have plumbing with lead solder or brass fixtures (which contain lead), the lead is more likely to leach into hot water than cold water. Instead of using the hot water tap, heat cold water on the stove or in the microwave. Charleston water is the water supplier for Charleston, SC. So I’m willing to trust them. FWIW, my dad used to say the same thing, particularly citing the lead solder in pipe joints as the hazard. ---
**Author:** ![KneadToKnow](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kneadtoknow/32/3999_2.png) [@KneadToKnow](https://boards.straightdope.com/u/KneadToKnow)\ **Post date:** [December 20, 2011, 9:53pm UTC](https://boards.straightdope.com/t/drinks-from-the-hot-tap/606891/5 "2011-12-20T21:53:12Z")
Previous threads: > **[Water from domestic hot water system unhealthy?](https://boards.straightdope.com/sdmb/showthread.php?t=125929)** > > I have an ongoing debate of sorts with my wife and mother in law over this topic. They insist that one should not drink water from the hot water tap because, they say, it is unhealthy. When pressed as to why they mutter something about stagnant... > **[hot tap water](https://boards.straightdope.com/sdmb/showthread.php?t=156449)** > > In his book “Eight Weeks to Optimum Health”, Dr. Andrew Weil warns readers against drinking or cooking with tap water, particularly hot tap water, claiming it is “unfit for human consumption”. I don’t have the book in front of me, but the reason he... > **[Is water from hot tap safe to drink?](https://boards.straightdope.com/sdmb/showthread.php?t=223695)** > > Instructions for coffee, tea, oatmeal, etc. often specify you start with cold water and then heat to boiling. Isn’t the hot water the same, only hotter? Unless your hot water tastes of iron (which can happen in the cold pipes as well), what’s the... > **[Is Hot Water Lead REALLY Killing Me?](https://boards.straightdope.com/sdmb/showthread.php?t=502808)** > > In a recent column, noted brainiac Marilyn Vos Savant posits that I shouldn’t use the hot water that comes out of my tap initially due to lead dangers. Call me skeptical, but this sounds like B.S. Here’s the actual column. Is she right or horribly... ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [December 20, 2011, 9:58pm UTC](https://boards.straightdope.com/t/drinks-from-the-hot-tap/606891/6 "2011-12-20T21:58:43Z")
It depends. If you have a typical water heater, like most folks these days, there are two concerns. The first is a higher concentration of impurities from your household plumbing, since hot water dissolves more impurities than cold water and the hot water in the tank tends to sit for a while. The second concern is that a lot of folks keep their hot water temperature much lower these days than they did in the past, both to conserve energy and also to make their water heaters last longer. The result is that bacteria that would have been killed in the older days of hotter water can now thrive at the more common lower temperatures. On the other hand, if your hot water is heated on demand rather than sitting in a tank, then neither of the above issues really applies. If you have an old fashioned boiler furnace like I do, or you have a new-fangled on-demand electric heater that heats the water right before it comes out of your faucet, then there is no tank where hot water sits and absorbs lead and other metals from your plumbing, and no tank for bacteria to grow in either. The hot water in both of these systems was cold water right before you needed it, so it really doesn’t matter. Most homes these days have a hot water tank. ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [December 20, 2011, 10:04pm UTC](https://boards.straightdope.com/t/drinks-from-the-hot-tap/606891/7 "2011-12-20T22:04:25Z")
I’ve heard also that the hot tap has less dissolved gas which effects the taste, though if your going to heat up the water anyway I’m not sure if there is going to be a difference. ---
**Author:** ![gatorslap](https://avatars.discourse-cdn.com/v4/letter/g/bb73d2/32.png) [@gatorslap](https://boards.straightdope.com/u/gatorslap)\ **Post date:** [December 20, 2011, 10:08pm UTC](https://boards.straightdope.com/t/drinks-from-the-hot-tap/606891/8 "2011-12-20T22:08:37Z")
What if you have an instant hot water dispenser installed by your kitchen faucet? Are those things somehow dangerous? ---
**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\ **Post date:** [December 20, 2011, 10:32pm UTC](https://boards.straightdope.com/t/drinks-from-the-hot-tap/606891/9 "2011-12-20T22:32:38Z")
another issue is turbidity, stuff that doesn’t dissolve in the water. solids can settle out of your water in your hot water tank. the tank, glass lined, will also have a sacrificial anode which corrodes and has particles settle from. some of these solids get get stirred up and come with the water. ---
**Author:** ![KneadToKnow](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kneadtoknow/32/3999_2.png) [@KneadToKnow](https://boards.straightdope.com/u/KneadToKnow)\ **Post date:** [December 20, 2011, 10:39pm UTC](https://boards.straightdope.com/t/drinks-from-the-hot-tap/606891/10 "2011-12-20T22:39:54Z")
> [@gatorslap](#): > > What if you have an instant hot water dispenser installed by your kitchen faucet? Are those things somehow dangerous? If I understand those correctly, they heat the water right there under your countertop, and are specifically designed to produce hot drinking water, so I would think any of the concerns associated with hot tap water would have been taken into consideration with those. ---
**Author:** ![Digital\_is\_the\_new\_Analog](https://avatars.discourse-cdn.com/v4/letter/d/a88e4f/32.png) [@Digital\_is\_the\_new\_Analog](https://boards.straightdope.com/u/Digital_is_the_new_Analog)\ **Post date:** [December 21, 2011, 1:57am UTC](https://boards.straightdope.com/t/drinks-from-the-hot-tap/606891/11 "2011-12-21T01:57:43Z")
If you do have a hot water tank, and you empty it occasionally, you probably have seen the crap that tends to collect in there. That can be a turn-off for drinking the water. -D/a ---
**Author:** ![lazybratsche](https://avatars.discourse-cdn.com/v4/letter/l/ba8739/32.png) [@lazybratsche](https://boards.straightdope.com/u/lazybratsche)\ **Post date:** [December 21, 2011, 1:06pm UTC](https://boards.straightdope.com/t/drinks-from-the-hot-tap/606891/12 "2011-12-21T13:06:50Z")
In all of these discussions, including all of the links to various public health officials saying “Don’t Drink Hot Water”, I’ve never seen any actual data. Yes, the mechanism sounds vaguely plausible: hot water can hold more solutes, or can dissolve more metals from the piping. But I’d love to see some actual measurements of water quality from typical household hot water sources as compared to the same cold water source (and upstream municipal supply). For example, what might actually happen in the worst case sort of scenario of an old house with lots of lead solder? If the municipal water supply has (say) 5 ppb lead, would cold tap water have an increased level of, say, 10 ppb? Would the hot water then have an even higher level of 20 ppb? Or perhaps the differences would be negligible, i.e. the water only increases from 5 to 5.1 ppb in the short trip through household plumbing, and maybe all the way to 5.2 ppb if it’s hot.